The total area or space visible in a person's peripheral vision with the eye looking straightforward.
Method of measuring and mapping the scope of vision, from central to peripheral of each eye.
Visual impairments limiting one or more of the basic functions of the eye: visual acuity, dark adaptation, color vision, or peripheral vision. These may result from EYE DISEASES; OPTIC NERVE DISEASES; VISUAL PATHWAY diseases; OCCIPITAL LOBE diseases; OCULAR MOTILITY DISORDERS; and other conditions (From Newell, Ophthalmology: Principles and Concepts, 7th ed, p132).
Clarity or sharpness of OCULAR VISION or the ability of the eye to see fine details. Visual acuity depends on the functions of RETINA, neuronal transmission, and the interpretative ability of the brain. Normal visual acuity is expressed as 20/20 indicating that one can see at 20 feet what should normally be seen at that distance. Visual acuity can also be influenced by brightness, color, and contrast.
Area of the OCCIPITAL LOBE concerned with the processing of visual information relayed via VISUAL PATHWAYS.
The selecting and organizing of visual stimuli based on the individual's past experience.
The electric response evoked in the cerebral cortex by visual stimulation or stimulation of the visual pathways.
Set of cell bodies and nerve fibers conducting impulses from the eyes to the cerebral cortex. It includes the RETINA; OPTIC NERVE; optic tract; and geniculocalcarine tract.
Partial or complete loss of vision in one half of the visual field(s) of one or both eyes. Subtypes include altitudinal hemianopsia, characterized by a visual defect above or below the horizontal meridian of the visual field. Homonymous hemianopsia refers to a visual defect that affects both eyes equally, and occurs either to the left or right of the midline of the visual field. Binasal hemianopsia consists of loss of vision in the nasal hemifields of both eyes. Bitemporal hemianopsia is the bilateral loss of vision in the temporal fields. Quadrantanopsia refers to loss of vision in one quarter of the visual field in one or both eyes.
A localized defect in the visual field bordered by an area of normal vision. This occurs with a variety of EYE DISEASES (e.g., RETINAL DISEASES and GLAUCOMA); OPTIC NERVE DISEASES, and other conditions.
An ocular disease, occurring in many forms, having as its primary characteristics an unstable or a sustained increase in the intraocular pressure which the eye cannot withstand without damage to its structure or impairment of its function. The consequences of the increased pressure may be manifested in a variety of symptoms, depending upon type and severity, such as excavation of the optic disk, hardness of the eyeball, corneal anesthesia, reduced visual acuity, seeing of colored halos around lights, disturbed dark adaptation, visual field defects, and headaches. (Dictionary of Visual Science, 4th ed)
Glaucoma in which the angle of the anterior chamber is open and the trabecular meshwork does not encroach on the base of the iris.
Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.
Conditions which produce injury or dysfunction of the second cranial or optic nerve, which is generally considered a component of the central nervous system. Damage to optic nerve fibers may occur at or near their origin in the retina, at the optic disk, or in the nerve, optic chiasm, optic tract, or lateral geniculate nuclei. Clinical manifestations may include decreased visual acuity and contrast sensitivity, impaired color vision, and an afferent pupillary defect.
Mental process to visually perceive a critical number of facts (the pattern), such as characters, shapes, displays, or designs.
A condition in which the intraocular pressure is elevated above normal and which may lead to glaucoma.
The process in which light signals are transformed by the PHOTORECEPTOR CELLS into electrical signals which can then be transmitted to the brain.
A series of tests used to assess various functions of the eyes.
The portion of the optic nerve seen in the fundus with the ophthalmoscope. It is formed by the meeting of all the retinal ganglion cell axons as they enter the optic nerve.
The ability to detect sharp boundaries (stimuli) and to detect slight changes in luminance at regions without distinct contours. Psychophysical measurements of this visual function are used to evaluate visual acuity and to detect eye disease.
The pressure of the fluids in the eye.
The minimum amount of stimulus energy necessary to elicit a sensory response.
The positioning and accommodation of eyes that allows the image to be brought into place on the FOVEA CENTRALIS of each eye.
The blending of separate images seen by each eye into one composite image.
The real or apparent movement of objects through the visual field.
Focusing on certain aspects of current experience to the exclusion of others. It is the act of heeding or taking notice or concentrating.
Voluntary or reflex-controlled movements of the eye.
The awareness of the spatial properties of objects; includes physical space.
The X-shaped structure formed by the meeting of the two optic nerves. At the optic chiasm the fibers from the medial part of each retina cross to project to the other side of the brain while the lateral retinal fibers continue on the same side. As a result each half of the brain receives information about the contralateral visual field from both eyes.
An analogue of GAMMA-AMINOBUTYRIC ACID. It is an irreversible inhibitor of 4-AMINOBUTYRATE TRANSAMINASE, the enzyme responsible for the catabolism of GAMMA-AMINOBUTYRIC ACID. (From Martindale The Extra Pharmacopoeia, 31st ed)
The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.
The science dealing with the correlation of the physical characteristics of a stimulus, e.g., frequency or intensity, with the response to the stimulus, in order to assess the psychologic factors involved in the relationship.
Recording of electric potentials in the retina after stimulation by light.
The time from the onset of a stimulus until a response is observed.
Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.
Neurons of the innermost layer of the retina, the internal plexiform layer. They are of variable sizes and shapes, and their axons project via the OPTIC NERVE to the brain. A small subset of these cells act as photoreceptors with projections to the SUPRACHIASMATIC NUCLEUS, the center for regulating CIRCADIAN RHYTHM.
The inability to see or the loss or absence of perception of visual stimuli. This condition may be the result of EYE DISEASES; OPTIC NERVE DISEASES; OPTIC CHIASM diseases; or BRAIN DISEASES affecting the VISUAL PATHWAYS or OCCIPITAL LOBE.
An imaging method using LASERS that is used for mapping subsurface structure. When a reflective site in the sample is at the same optical path length (coherence) as the reference mirror, the detector observes interference fringes.
Methods and procedures for the diagnosis of diseases of the eye or of vision disorders.
Images seen by one eye.
An area approximately 1.5 millimeters in diameter within the macula lutea where the retina thins out greatly because of the oblique shifting of all layers except the pigment epithelium layer. It includes the sloping walls of the fovea (clivus) and contains a few rods in its periphery. In its center (foveola) are the cones most adapted to yield high visual acuity, each cone being connected to only one ganglion cell. (Cline et al., Dictionary of Visual Science, 4th ed)
Hereditary, progressive degeneration of the neuroepithelium of the retina characterized by night blindness and progressive contraction of the visual field.
Behavioral manifestations of cerebral dominance in which there is preferential use and superior functioning of either the left or the right side, as in the preferred use of the right hand or right foot.
Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.
Fields representing the joint interplay of electric and magnetic forces.
Vision considered to be inferior to normal vision as represented by accepted standards of acuity, field of vision, or motility. Low vision generally refers to visual disorders that are caused by diseases that cannot be corrected by refraction (e.g., MACULAR DEGENERATION; RETINITIS PIGMENTOSA; DIABETIC RETINOPATHY, etc.).
Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.
Ischemic injury to the OPTIC NERVE which usually affects the OPTIC DISK (optic neuropathy, anterior ischemic) and less frequently the retrobulbar portion of the nerve (optic neuropathy, posterior ischemic). The injury results from occlusion of arterial blood supply which may result from TEMPORAL ARTERITIS; ATHEROSCLEROSIS; COLLAGEN DISEASES; EMBOLISM; DIABETES MELLITUS; and other conditions. The disease primarily occurs in the sixth decade or later and presents with the sudden onset of painless and usually severe monocular visual loss. Anterior ischemic optic neuropathy also features optic disk edema with microhemorrhages. The optic disk appears normal in posterior ischemic optic neuropathy. (Glaser, Neuro-Ophthalmology, 2nd ed, p135)
An abrupt voluntary shift in ocular fixation from one point to another, as occurs in reading.
The coordination of a sensory or ideational (cognitive) process and a motor activity.
Examination of the interior of the eye with an ophthalmoscope.
Differential response to different stimuli.
Measurement of ocular tension (INTRAOCULAR PRESSURE) with a tonometer. (Cline, et al., Dictionary of Visual Science, 4th ed)
Processes and properties of the EYE as a whole or of any of its parts.
Cognitive disorders characterized by an impaired ability to perceive the nature of objects or concepts through use of the sense organs. These include spatial neglect syndromes, where an individual does not attend to visual, auditory, or sensory stimuli presented from one side of the body.
A form of GLAUCOMA in which chronic optic nerve damage and loss of vision normally attributable to buildup of intraocular pressure occurs despite prevailing conditions of normal intraocular pressure.
Retinal diseases refer to a diverse group of vision-threatening disorders that affect the retina's structure and function, including age-related macular degeneration, diabetic retinopathy, retinal detachment, retinitis pigmentosa, and macular edema, among others.
The sensory discrimination of a pattern shape or outline.
Posterior portion of the CEREBRAL HEMISPHERES responsible for processing visual sensory information. It is located posterior to the parieto-occipital sulcus and extends to the preoccipital notch.
Signals for an action; that specific portion of a perceptual field or pattern of stimuli to which a subject has learned to respond.
The aperture in the iris through which light passes.
A pair of ophthalmic lenses in a frame or mounting which is supported by the nose and ears. The purpose is to aid or improve vision. It does not include goggles or nonprescription sun glasses for which EYE PROTECTIVE DEVICES is available.
The concave interior of the eye, consisting of the retina, the choroid, the sclera, the optic disk, and blood vessels, seen by means of the ophthalmoscope. (Cline et al., Dictionary of Visual Science, 4th ed)
The anterior pair of the quadrigeminal bodies which coordinate the general behavioral orienting responses to visual stimuli, such as whole-body turning, and reaching.
Total loss of vision in all or part of the visual field due to bilateral OCCIPITAL LOBE (i.e., VISUAL CORTEX) damage or dysfunction. Anton syndrome is characterized by the psychic denial of true, organic cortical blindness. (Adams et al., Principles of Neurology, 6th ed, p460)
Awareness of oneself in relation to time, place and person.
Visualization of a vascular system after intravenous injection of a fluorescein solution. The images may be photographed or televised. It is used especially in studying the retinal and uveal vasculature.
Upper central part of the cerebral hemisphere. It is located posterior to central sulcus, anterior to the OCCIPITAL LOBE, and superior to the TEMPORAL LOBES.
Method of making images on a sensitized surface by exposure to light or other radiant energy.
The 2nd cranial nerve which conveys visual information from the RETINA to the brain. The nerve carries the axons of the RETINAL GANGLION CELLS which sort at the OPTIC CHIASM and continue via the OPTIC TRACTS to the brain. The largest projection is to the lateral geniculate nuclei; other targets include the SUPERIOR COLLICULI and the SUPRACHIASMATIC NUCLEI. Though known as the second cranial nerve, it is considered part of the CENTRAL NERVOUS SYSTEM.
Part of the DIENCEPHALON inferior to the caudal end of the dorsal THALAMUS. Includes the lateral geniculate body which relays visual impulses from the OPTIC TRACT to the calcarine cortex, and the medial geniculate body which relays auditory impulses from the lateral lemniscus to the AUDITORY CORTEX.
Imaging methods that result in sharp images of objects located on a chosen plane and blurred images located above or below the plane.
The point or frequency at which all flicker of an intermittent light stimulus disappears.
A species of the genus MACACA inhabiting India, China, and other parts of Asia. The species is used extensively in biomedical research and adapts very well to living with humans.
'Reading' in a medical context often refers to the act or process of a person interpreting and comprehending written or printed symbols, such as letters or words, for the purpose of deriving information or meaning from them.
Persons with loss of vision such that there is an impact on activities of daily living.
Theoretical representations that simulate the behavior or activity of the neurological system, processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
Relatively bright light, or the dazzling sensation of relatively bright light, which produces unpleasantness or discomfort, or which interferes with optimal VISION, OCULAR. (Cline et al., Dictionary of Visual Science, 4th ed)
Swelling of the OPTIC DISK, usually in association with increased intracranial pressure, characterized by hyperemia, blurring of the disk margins, microhemorrhages, blind spot enlargement, and engorgement of retinal veins. Chronic papilledema may cause OPTIC ATROPHY and visual loss. (Miller et al., Clinical Neuro-Ophthalmology, 4th ed, p175)
Areas of attractive or repulsive force surrounding MAGNETS.
The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.
Deviations from the average or standard indices of refraction of the eye through its dioptric or refractive apparatus.
Elements of limited time intervals, contributing to particular results or situations.
The absence or restriction of the usual external sensory stimuli to which the individual responds.
The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)
Adjustment of the eyes under conditions of low light. The sensitivity of the eye to light is increased during dark adaptation.
Inflammation of the optic nerve. Commonly associated conditions include autoimmune disorders such as MULTIPLE SCLEROSIS, infections, and granulomatous diseases. Clinical features include retro-orbital pain that is aggravated by eye movement, loss of color vision, and contrast sensitivity that may progress to severe visual loss, an afferent pupillary defect (Marcus-Gunn pupil), and in some instances optic disc hyperemia and swelling. Inflammation may occur in the portion of the nerve within the globe (neuropapillitis or anterior optic neuritis) or the portion behind the globe (retrobulbar neuritis or posterior optic neuritis).
A nonspecific term referring to impaired vision. Major subcategories include stimulus deprivation-induced amblyopia and toxic amblyopia. Stimulus deprivation-induced amblyopia is a developmental disorder of the visual cortex. A discrepancy between visual information received by the visual cortex from each eye results in abnormal cortical development. STRABISMUS and REFRACTIVE ERRORS may cause this condition. Toxic amblyopia is a disorder of the OPTIC NERVE which is associated with ALCOHOLISM, tobacco SMOKING, and other toxins and as an adverse effect of the use of some medications.
Defects of color vision are mainly hereditary traits but can be secondary to acquired or developmental abnormalities in the CONES (RETINA). Severity of hereditary defects of color vision depends on the degree of mutation of the ROD OPSINS genes (on X CHROMOSOME and CHROMOSOME 3) that code the photopigments for red, green and blue.
The effect of environmental or physiological factors on the driver and driving ability. Included are driving fatigue, and the effect of drugs, disease, and physical disabilities on driving.
Function of the human eye that is used in bright illumination or in daylight (at photopic intensities). Photopic vision is performed by the three types of RETINAL CONE PHOTORECEPTORS with varied peak absorption wavelengths in the color spectrum (from violet to red, 400 - 700 nm).
Conditions which affect the structure or function of the pupil of the eye, including disorders of innervation to the pupillary constrictor or dilator muscles, and disorders of pupillary reflexes.
The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.
Mental processing of chromatic signals (COLOR VISION) from the eye by the VISUAL CORTEX where they are converted into symbolic representations. Color perception involves numerous neurons, and is influenced not only by the distribution of wavelengths from the viewed object, but also by its background color and brightness contrast at its boundary.
Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)
A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.
The worsening of a disease over time. This concept is most often used for chronic and incurable diseases where the stage of the disease is an important determinant of therapy and prognosis.
An oval area in the retina, 3 to 5 mm in diameter, usually located temporal to the posterior pole of the eye and slightly below the level of the optic disk. It is characterized by the presence of a yellow pigment diffusely permeating the inner layers, contains the fovea centralis in its center, and provides the best phototropic visual acuity. It is devoid of retinal blood vessels, except in its periphery, and receives nourishment from the choriocapillaris of the choroid. (From Cline et al., Dictionary of Visual Science, 4th ed)
A technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.
Perception of three-dimensionality.
The adjustment of the eye to variations in the intensity of light. Light adaptation is the adjustment of the eye when the light threshold is increased; DARK ADAPTATION when the light is greatly reduced. (From Cline et al., Dictionary of Visual Science, 4th ed)
Misalignment of the visual axes of the eyes. In comitant strabismus the degree of ocular misalignment does not vary with the direction of gaze. In noncomitant strabismus the degree of misalignment varies depending on direction of gaze or which eye is fixating on the target. (Miller, Walsh & Hoyt's Clinical Neuro-Ophthalmology, 4th ed, p641)
The ability to respond to segments of the perceptual experience rather than to the whole.
Dominance of one cerebral hemisphere over the other in cerebral functions.
A form of glaucoma in which the intraocular pressure increases because the angle of the anterior chamber is blocked and the aqueous humor cannot drain from the anterior chamber.
A genus of the subfamily CERCOPITHECINAE, family CERCOPITHECIDAE, consisting of 16 species inhabiting forests of Africa, Asia, and the islands of Borneo, Philippines, and Celebes.
Atrophy of the optic disk which may be congenital or acquired. This condition indicates a deficiency in the number of nerve fibers which arise in the RETINA and converge to form the OPTIC DISK; OPTIC NERVE; OPTIC CHIASM; and optic tracts. GLAUCOMA; ISCHEMIA; inflammation, a chronic elevation of intracranial pressure, toxins, optic nerve compression, and inherited conditions (see OPTIC ATROPHIES, HEREDITARY) are relatively common causes of this condition.
Any surgical procedure for treatment of glaucoma by means of puncture or reshaping of the trabecular meshwork. It includes goniotomy, trabeculectomy, and laser perforation.
An illusion of vision usually affecting spatial relations.
The sensory interpretation of the dimensions of objects.
Diseases affecting the eye.
Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.
A subjective visual sensation with the eyes closed and in the absence of light. Phosphenes can be spontaneous, or induced by chemical, electrical, or mechanical (pressure) stimuli which cause the visual field to light up without optical inputs.
Photosensitive afferent neurons located primarily within the FOVEA CENTRALIS of the MACULA LUTEA. There are three major types of cone cells (red, blue, and green) whose photopigments have different spectral sensitivity curves. Retinal cone cells operate in daylight vision (at photopic intensities) providing color recognition and central visual acuity.
The act of knowing or the recognition of a distance by recollective thought, or by means of a sensory process which is under the influence of set and of prior experience.
The organ of sight constituting a pair of globular organs made up of a three-layered roughly spherical structure specialized for receiving and responding to light.
A condition marked by raised intracranial pressure and characterized clinically by HEADACHES; NAUSEA; PAPILLEDEMA, peripheral constriction of the visual fields, transient visual obscurations, and pulsatile TINNITUS. OBESITY is frequently associated with this condition, which primarily affects women between 20 and 44 years of age. Chronic PAPILLEDEMA may lead to optic nerve injury (see OPTIC NERVE DISEASES) and visual loss (see BLINDNESS).
Application of tests and examinations to identify visual defects or vision disorders occurring in specific populations, as in school children, the elderly, etc. It is differentiated from VISION TESTS, which are given to evaluate/measure individual visual performance not related to a specific population.
The illumination of an environment and the arrangement of lights to achieve an effect or optimal visibility. Its application is in domestic or in public settings and in medical and non-medical environments.
Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.
Degenerative changes in the RETINA usually of older adults which results in a loss of vision in the center of the visual field (the MACULA LUTEA) because of damage to the retina. It occurs in dry and wet forms.
The visually perceived property of objects created by absorption or reflection of specific wavelengths of light.
Neoplasms which arise from or metastasize to the PITUITARY GLAND. The majority of pituitary neoplasms are adenomas, which are divided into non-secreting and secreting forms. Hormone producing forms are further classified by the type of hormone they secrete. Pituitary adenomas may also be characterized by their staining properties (see ADENOMA, BASOPHIL; ADENOMA, ACIDOPHIL; and ADENOMA, CHROMOPHOBE). Pituitary tumors may compress adjacent structures, including the HYPOTHALAMUS, several CRANIAL NERVES, and the OPTIC CHIASM. Chiasmal compression may result in bitemporal HEMIANOPSIA.
The misinterpretation of a real external, sensory experience.
Function of the human eye that is used in dim illumination (scotopic intensities) or at nighttime. Scotopic vision is performed by RETINAL ROD PHOTORECEPTORS with high sensitivity to light and peak absorption wavelength at 507 nm near the blue end of the spectrum.
Constriction of the pupil in response to light stimulation of the retina. It refers also to any reflex involving the iris, with resultant alteration of the diameter of the pupil. (Cline et al., Dictionary of Visual Science, 4th ed)
Lack of correspondence between the way a stimulus is commonly perceived and the way an individual perceives it under given conditions.
Type of vision test used to determine COLOR VISION DEFECTS.
The functional superiority and preferential use of one eye over the other. The term is usually applied to superiority in sighting (VISUAL PERCEPTION) or motor task but not difference in VISUAL ACUITY or dysfunction of one of the eyes. Ocular dominance can be modified by visual input and NEUROTROPHIC FACTORS.
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
An optical source that emits photons in a coherent beam. Light Amplification by Stimulated Emission of Radiation (LASER) is brought about using devices that transform light of varying frequencies into a single intense, nearly nondivergent beam of monochromatic radiation. Lasers operate in the infrared, visible, ultraviolet, or X-ray regions of the spectrum.
Lower lateral part of the cerebral hemisphere responsible for auditory, olfactory, and semantic processing. It is located inferior to the lateral fissure and anterior to the OCCIPITAL LOBE.
A surgical specialty concerned with the structure and function of the eye and the medical and surgical treatment of its defects and diseases.
Albinism affecting the eye in which pigment of the hair and skin is normal or only slightly diluted. The classic type is X-linked (Nettleship-Falls), but an autosomal recessive form also exists. Ocular abnormalities may include reduced pigmentation of the iris, nystagmus, photophobia, strabismus, and decreased visual acuity.
A refractive error in which rays of light entering the EYE parallel to the optic axis are brought to a focus in front of the RETINA when accommodation (ACCOMMODATION, OCULAR) is relaxed. This results from an overly curved CORNEA or from the eyeball being too long from front to back. It is also called nearsightedness.
A genus of the family Lorisidae having four species which inhabit the forests and bush regions of Africa south of the Sahara and some nearby islands. The four species are G. alleni, G. crassicaudatus, G. demidovii, and G. senegalensis. There is another genus, Euoticus, containing two species which some authors have included in the Galago genus.
Government required written and driving test given to individuals prior to obtaining an operator's license.
A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.
Refraction of LIGHT effected by the media of the EYE.
The interference of one perceptual stimulus with another causing a decrease or lessening in perceptual effectiveness.
Optic disk bodies composed primarily of acid mucopolysaccharides that may produce pseudopapilledema (elevation of the optic disk without associated INTRACRANIAL HYPERTENSION) and visual field deficits. Drusen may also occur in the retina (see RETINAL DRUSEN). (Miller et al., Clinical Neuro-Ophthalmology, 4th ed, p355)
Examination of the angle of the anterior chamber of the eye with a specialized optical instrument (gonioscope) or a contact prism lens.
Surgery performed on the eye or any of its parts.
Recording of the average amplitude of the resting potential arising between the cornea and the retina in light and dark adaptation as the eyes turn a standard distance to the right and the left. The increase in potential with light adaptation is used to evaluate the condition of the retinal pigment epithelium.
The professional practice of primary eye and vision care that includes the measurement of visual refractive power and the correction of visual defects with lenses or glasses.
The non-genetic biological changes of an organism in response to challenges in its ENVIRONMENT.
Benign and malignant neoplasms that arise from the optic nerve or its sheath. OPTIC NERVE GLIOMA is the most common histologic type. Optic nerve neoplasms tend to cause unilateral visual loss and an afferent pupillary defect and may spread via neural pathways to the brain.
An objective determination of the refractive state of the eye (NEARSIGHTEDNESS; FARSIGHTEDNESS; ASTIGMATISM). By using a RETINOSCOPE, the amount of correction and the power of lens needed can be determined.
Partial or complete opacity on or in the lens or capsule of one or both eyes, impairing vision or causing blindness. The many kinds of cataract are classified by their morphology (size, shape, location) or etiology (cause and time of occurrence). (Dorland, 27th ed)
A neurosurgical procedure that removes the anterior TEMPORAL LOBE including the medial temporal structures of CEREBRAL CORTEX; AMYGDALA; HIPPOCAMPUS; and the adjacent PARAHIPPOCAMPAL GYRUS. This procedure is generally used for the treatment of intractable temporal epilepsy (EPILEPSY, TEMPORAL LOBE).
Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.
The anterior portion of the head that includes the skin, muscles, and structures of the forehead, eyes, nose, mouth, cheeks, and jaw.
Recording of electric currents developed in the brain by means of electrodes applied to the scalp, to the surface of the brain, or placed within the substance of the brain.
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
Relatively permanent change in behavior that is the result of past experience or practice. The concept includes the acquisition of knowledge.
Instruments used to observe distant objects.
Normal nystagmus produced by looking at objects moving across the field of vision.
Electrical responses recorded from nerve, muscle, SENSORY RECEPTOR, or area of the CENTRAL NERVOUS SYSTEM following stimulation. They range from less than a microvolt to several microvolts. The evoked potential can be auditory (EVOKED POTENTIALS, AUDITORY), somatosensory (EVOKED POTENTIALS, SOMATOSENSORY), visual (EVOKED POTENTIALS, VISUAL), or motor (EVOKED POTENTIALS, MOTOR), or other modalities that have been reported.
Use of sound to elicit a response in the nervous system.
Statistical models in which the value of a parameter for a given value of a factor is assumed to be equal to a + bx, where a and b are constants. The models predict a linear regression.
Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
A species of the genus MACACA which typically lives near the coast in tidal creeks and mangrove swamps primarily on the islands of the Malay peninsula.
A transitional diencephalic zone of the thalamus consisting of complex and varied cells lying caudal to the VENTRAL POSTEROLATERAL NUCLEUS, medial to the rostral part of the PULVINAR, and dorsal to the MEDIAL GENICULATE BODY. It contains the limitans, posterior, suprageniculate, and submedial nuclei.
The use of an aberrometer to measure eye tissue imperfections or abnormalities based on the way light passes through the eye which affects the ability of the eye to focus properly.
Learning that is manifested in the ability to respond differentially to various stimuli.
The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time.
The tendency to perceive an incomplete pattern or object as complete or whole. This includes the Gestalt Law of Closure.
Application of computer programs designed to assist the physician in solving a diagnostic problem.
The difference between two images on the retina when looking at a visual stimulus. This occurs since the two retinas do not have the same view of the stimulus because of the location of our eyes. Thus the left eye does not get exactly the same view as the right eye.
The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.
A technique of diagnostic imaging of RETINA or CORNEA of the human eye involving the measurement and interpretation of polarizing ELECTROMAGNETIC WAVES such as radio or light waves. It is helpful in the diagnosis of GLAUCOMA; MACULAR DEGENERATION; and other retinal disorders.
The removal of a cataractous CRYSTALLINE LENS from the eye.
Loss of the ability to comprehend the meaning or recognize the importance of various forms of stimulation that cannot be attributed to impairment of a primary sensory modality. Tactile agnosia is characterized by an inability to perceive the shape and nature of an object by touch alone, despite unimpaired sensation to light touch, position, and other primary sensory modalities.
Eye movements that are slow, continuous, and conjugate and occur when a fixed object is moved slowly.
A beta-adrenergic antagonist similar in action to PROPRANOLOL. The levo-isomer is the more active. Timolol has been proposed as an antihypertensive, antiarrhythmic, antiangina, and antiglaucoma agent. It is also used in the treatment of MIGRAINE DISORDERS and tremor.
The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulchi. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions.
Computer-based representation of physical systems and phenomena such as chemical processes.
Positive test results in subjects who do not possess the attribute for which the test is conducted. The labeling of healthy persons as diseased when screening in the detection of disease. (Last, A Dictionary of Epidemiology, 2d ed)
The sudden loss of blood supply to the PITUITARY GLAND, leading to tissue NECROSIS and loss of function (PANHYPOPITUITARISM). The most common cause is hemorrhage or INFARCTION of a PITUITARY ADENOMA. It can also result from acute hemorrhage into SELLA TURCICA due to HEAD TRAUMA; INTRACRANIAL HYPERTENSION; or other acute effects of central nervous system hemorrhage. Clinical signs include severe HEADACHE; HYPOTENSION; bilateral visual disturbances; UNCONSCIOUSNESS; and COMA.
Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory.
Controlled operation of an apparatus, process, or system by mechanical or electronic devices that take the place of human organs of observation, effort, and decision. (From Webster's Collegiate Dictionary, 1993)
Mechanical compression of nerves or nerve roots from internal or external causes. These may result in a conduction block to nerve impulses (due to MYELIN SHEATH dysfunction) or axonal loss. The nerve and nerve sheath injuries may be caused by ISCHEMIA; INFLAMMATION; or a direct mechanical effect.
Psychophysical technique that permits the estimation of the bias of the observer as well as detectability of the signal (i.e., stimulus) in any sensory modality. (From APA, Thesaurus of Psychological Index Terms, 8th ed.)
Methods and procedures for recording EYE MOVEMENTS.
Removal of the whole or part of the vitreous body in treating endophthalmitis, diabetic retinopathy, retinal detachment, intraocular foreign bodies, and some types of glaucoma.
The administration of substances into the eye with a hypodermic syringe.
Devices that help people with impaired sensory responses.
Drugs used to prevent SEIZURES or reduce their severity.
Physical motion, i.e., a change in position of a body or subject as a result of an external force. It is distinguished from MOVEMENT, a process resulting from biological activity.
Filarial infection of the eyes transmitted from person to person by bites of Onchocerca volvulus-infected black flies. The microfilariae of Onchocerca are thus deposited beneath the skin. They migrate through various tissues including the eye. Those persons infected have impaired vision and up to 20% are blind. The incidence of eye lesions has been reported to be as high as 30% in Central America and parts of Africa.
The capacity of the NERVOUS SYSTEM to change its reactivity as the result of successive activations.
Pieces of glass or other transparent materials used for magnification or increased visual acuity.
The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
A graphic means for assessing the ability of a screening test to discriminate between healthy and diseased persons; may also be used in other studies, e.g., distinguishing stimuli responses as to a faint stimuli or nonstimuli.
A benign pituitary-region neoplasm that originates from Rathke's pouch. The two major histologic and clinical subtypes are adamantinous (or classical) craniopharyngioma and papillary craniopharyngioma. The adamantinous form presents in children and adolescents as an expanding cystic lesion in the pituitary region. The cystic cavity is filled with a black viscous substance and histologically the tumor is composed of adamantinomatous epithelium and areas of calcification and necrosis. Papillary craniopharyngiomas occur in adults, and histologically feature a squamous epithelium with papillations. (From Joynt, Clinical Neurology, 1998, Ch14, p50)
Computer programs based on knowledge developed from consultation with experts on a problem, and the processing and/or formalizing of this knowledge using these programs in such a manner that the problems may be solved.
The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.
The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.
In invertebrate zoology, a lateral lobe of the FOREBRAIN in certain ARTHROPODS. In vertebrate zoology, either of the corpora bigemina of non-mammalian VERTEBRATES. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1329)
Pathologic conditions affecting the BRAIN, which is composed of the intracranial components of the CENTRAL NERVOUS SYSTEM. This includes (but is not limited to) the CEREBRAL CORTEX; intracranial white matter; BASAL GANGLIA; THALAMUS; HYPOTHALAMUS; BRAIN STEM; and CEREBELLUM.
Electrodes with an extremely small tip, used in a voltage clamp or other apparatus to stimulate or record bioelectric potentials of single cells intracellularly or extracellularly. (Dorland, 28th ed)
A meshlike structure composed of interconnecting nerve cells that are separated at the synaptic junction or joined to one another by cytoplasmic processes. In invertebrates, for example, the nerve net allows nerve impulses to spread over a wide area of the net because synapses can pass information in any direction.

On the neural correlates of visual perception. (1/4118)

Neurological findings suggest that the human striate cortex (V1) is an indispensable component of a neural substratum subserving static achromatic form perception in its own right and not simply as a central distributor of retinally derived information to extrastriate visual areas. This view is further supported by physiological evidence in primates that the finest-grained conjoined representation of spatial detail and retinotopic localization that underlies phenomenal visual experience for local brightness discriminations is selectively represented at cortical levels by the activity of certain neurons in V1. However, at first glance, support for these ideas would appear to be undermined by incontrovertible neurological evidence (visual hemineglect and the simultanagnosias) and recent psychophysical results on 'crowding' that confirm that activation of neurons in V1 may, at times, be insufficient to generate a percept. Moreover, a recent proposal suggests that neural correlates of visual awareness must project directly to those in executive space, thus automatically excluding V1 from a related perceptual space because V1 lacks such direct projections. Both sets of concerns are, however, resolved within the context of adaptive resonance theories. Recursive loops, linking the dorsal lateral geniculate nucleus (LGN) through successive cortical visual areas to the temporal lobe by means of a series of ascending and descending pathways, provide a neuronal substratum at each level within a modular framework for mutually consistent descriptions of sensory data. At steady state, such networks obviate the necessity that neural correlates of visual experience project directly to those in executive space because a neural phenomenal perceptual space subserving form vision is continuously updated by information from an object recognition space equivalent to that destined to reach executive space. Within this framework, activity in V1 may engender percepts that accompany figure-ground segregations only when dynamic incongruities are resolved both within and between ascending and descending streams. Synchronous neuronal activity on a short timescale within and across cortical areas, proposed and sometimes observed as perceptual correlates, may also serve as a marker that a steady state has been achieved, which, in turn, may be a requirement for the longer time constants that accompany the emergence and stability of perceptual states compared to the faster dynamics of adapting networks and the still faster dynamics of individual action potentials. Finally, the same consensus of neuronal activity across ascending and descending pathways linking multiple cortical areas that in anatomic sequence subserve phenomenal visual experiences and object recognition may underlie the normal unity of conscious experience.  (+info)

Transient and permanent deficits in motion perception after lesions of cortical areas MT and MST in the macaque monkey. (2/4118)

We examined the nature and the selectivity of the motion deficits produced by lesions of extrastriate areas MT and MST. Lesions were made by injecting ibotenic acid into the representation of the left visual field in two macaque monkeys. The monkeys discriminated two stimuli that differed either in stimulus direction or orientation. Direction and orientation discrimination were assessed by measuring thresholds with gratings and random-dots placed in the intact or lesioned visual fields. At the start of behavioral testing, we found pronounced, motion-specific deficits in thresholds for all types of moving stimuli, including pronounced elevations in contrast thresholds and in signal-to-noise thresholds measured with moving gratings, as well as deficits in direction range thresholds and motion coherence measured with random-dot stimuli. In addition, the accuracy of direction discrimination was reduced at smaller spatial displacements (i.e. step sizes), suggesting an increase in spatial scale of the residual directional mechanism. Subsequent improvements in thresholds were seen with all motion stimuli, as behavioral training progressed, and these improvements occurred only with extensive behavioral testing in the lesioned visual field. These improvements were particularly pronounced for stimuli not masked by noise. On the other hand, deficits in the ability to extract motion from noisy stimuli and in the accuracy of direction discrimination persisted despite extensive behavioral training. These results demonstrate the importance of areas MT and MST for the perception of motion direction, particularly in the presence of noise. In addition, they provide evidence for the importance of behavioral training for functional recovery after cortical lesions. The data also strongly support the idea of functional specialization of areas MT and MST for motion processing.  (+info)

Retinotopic mapping of lateral geniculate nucleus in humans using functional magnetic resonance imaging. (3/4118)

Subcortical nuclei in the thalamus, which play an important role in many functions of the human brain, provide challenging targets for functional mapping with neuroimaging techniques because of their small sizes and deep locations. In this study, we explore the capability of high-resolution functional magnetic resonance imaging at 4 Tesla for mapping the retinotopic organization in the lateral geniculate nucleus (LGN). Our results show that the hemifield visual stimulation only activates LGN in the contralateral hemisphere, and the lower-field and upper-field visual stimulations activate the superior and inferior portion of LGN, respectively. These results reveal a similar retinotopic organization between the human and nonhuman primate LGN and between LGN and the primary visual cortex. We conclude that high-resolution functional magnetic resonance imaging is capable of functional mapping of suborganizations in small nuclei together with cortical activation. This will have an impact for studying the thalamocortical networks in the human brain.  (+info)

Early visual experience shapes the representation of auditory space in the forebrain gaze fields of the barn owl. (4/4118)

Auditory spatial information is processed in parallel forebrain and midbrain pathways. Sensory experience early in life has been shown to exert a powerful influence on the representation of auditory space in the midbrain space-processing pathway. The goal of this study was to determine whether early experience also shapes the representation of auditory space in the forebrain. Owls were raised wearing prismatic spectacles that shifted the visual field in the horizontal plane. This manipulation altered the relationship between interaural time differences (ITDs), the principal cue used for azimuthal localization, and locations of auditory stimuli in the visual field. Extracellular recordings were used to characterize ITD tuning in the auditory archistriatum (AAr), a subdivision of the forebrain gaze fields, in normal and prism-reared owls. Prism rearing altered the representation of ITD in the AAr. In prism-reared owls, unit tuning for ITD was shifted in the adaptive direction, according to the direction of the optical displacement imposed by the spectacles. Changes in ITD tuning involved the acquisition of unit responses to adaptive ITD values and, to a lesser extent, the elimination of responses to nonadaptive (previously normal) ITD values. Shifts in ITD tuning in the AAr were similar to shifts in ITD tuning observed in the optic tectum of the same owls. This experience-based adjustment of binaural tuning in the AAr helps to maintain mutual registry between the forebrain and midbrain representations of auditory space and may help to ensure consistent behavioral responses to auditory stimuli.  (+info)

Test-retest variability of frequency-doubling perimetry and conventional perimetry in glaucoma patients and normal subjects. (5/4118)

PURPOSE: To compare the test-retest variability characteristics of frequency-doubling perimetry, a new perimetric test, with those of conventional perimetry in glaucoma patients and normal control subjects. METHODS: The study sample contained 64 patients and 47 normal subjects aged 66.16+/-11.86 and 64.26+/-7.99 years (mean +/- SD), respectively. All subjects underwent frequency-doubling perimetry (using the threshold mode) and conventional perimetry (using program 30-2 of the Humphrey Field Analyzer; Humphrey Instruments, San Leandro, CA) in one randomly selected eye. Each test was repeated at 1-week intervals for five tests with each technique over 4 weeks. Empirical 5th and 95th percentiles of the distribution of threshold deviations at retest were determined for all combinations of single tests and mean of two tests, stratified by threshold deviation. The influence of visual field eccentricity and overall visual field loss on variability also were examined. RESULTS: Mean test time with frequency-doubling perimetry in patients and normal control subjects was 5.90 and 5.25 minutes, respectively, and with conventional perimetry was 17.20 and 14.01 minutes, respectively. In patients, there was a significant correlation between the results of the two techniques, in the full field and in quadrants, whereas in normal subjects there was no such correlation. In patients, the retest variability of conventional perimetry in locations with 20-dB loss was 120% (single tests) and 127% (mean tests) higher compared with that in locations with 0-dB loss. Comparative figures for frequency-doubling perimetry were 40% and 47%, respectively. Variability also increased more with threshold deviation in normal subjects tested with conventional perimetry. In both patients and normal subjects, variability increased with visual field eccentricity in conventional perimetry, but not in frequency-doubling perimetry. Both techniques showed an increase in variability with overall visual field damage. CONCLUSIONS: Frequency-doubling perimetry has different test-retest variability characteristics than conventional perimetry and may have potential for monitoring glaucomatous field damage.  (+info)

Selective horizontal dysmetropsia following prestriate lesion. (6/4118)

We describe a patient (P.S.) who, following a right prestriate lesion, reported that objects in the left visual field appeared distorted and smaller than those on the right. Other aspects of visual processing were remarkably unaffected. We carried out a series of size comparison tests using simple or complex stimuli and requiring different types of behavioural responses. We found that P.S. significantly underestimated the size of stimuli presented in her left visual field. When comparison tasks involved stimuli placed along the vertical axis or in the right visual field, P.S. performed well. The vertical and horizontal components of size distortion were found to be differentially affected. We conclude that size processing may be dissociated from other aspects of visual processing, such as form or colour processing, and depends critically on part of the occipital, prestriate areas (Brodmann areas 18-19).  (+info)

Evaluation of focal defects of the nerve fiber layer using optical coherence tomography. (7/4118)

OBJECTIVE: To analyze glaucomatous eyes with known focal defects of the nerve fiber layer (NFL), relating optical coherence tomography (OCT) findings to clinical examination, NFL and stereoscopic optic nerve head (ONH) photography, and Humphrey 24-2 visual fields. DESIGN: Cross-sectional prevalence study. PARTICIPANTS: The authors followed 19 patients in the study group and 14 patients in the control group. INTERVENTION: Imaging with OCT was performed circumferentially around the ONH with a circle diameter of 3.4 mm using an internal fixation technique. One hundred OCT scan points taken within 2.5 seconds were analyzed. MAIN OUTCOME MEASURES: Measurements of NFL thickness using OCT were performed. RESULTS: In most eyes with focal NFL defects, OCTs showed significant thinning of the NFL in areas closely corresponding to focal defects visible on clinical examination, to red-free photographs, and to defects on the Humphrey visual fields. Optical coherence tomography enabled the detection of focal defects in the NFL with a sensitivity of 65% and a specificity of 81%. CONCLUSION: Analysis of NFL thickness in eyes with focal defects showed good structural and functional correlation with clinical parameters. Optical coherence tomography contributes to the identification of focal defects in the NFL that occur in early stages of glaucoma.  (+info)

Cross-correlation study of the temporal interactions between areas V1 and V2 of the macaque monkey. (8/4118)

Cross-correlation studies performed in cat visual cortex have shown that neurons in different cortical areas of the same hemisphere or in corresponding areas of opposite hemispheres tend to synchronize their activities. The presence of synchronization may be related to the parallel organization of the cat visual system, in which different cortical areas can be activated in parallel from the lateral geniculate nucleus. We wanted to determine whether interareal synchronization of firing can also be observed in the monkey, in which cortical areas are thought to be organized in a hierarchy spanning different levels. Cross-correlation histograms (CCHs) were calculated from pairs of single or pairs of multiunit activities simultaneously recorded in areas V1 and V2 of paralyzed and anesthetized macaque monkeys. Moving bars and flashed bars were used as stimuli. The shift predictor was calculated and subtracted from the raw CCH to reveal interactions of neuronal origin in isolation. Significant CCH peaks, indicating interactions of neuronal origin, were obtained in 11% of the dual single-unit recordings and 46% of the dual multiunit recordings with moving bars. The incidence of nonflat CCHs with flashed bars was 29 and 78%, respectively. For the pairs of recording sites where both flashed and moving stimuli were used, the incidences of significant CCHs were very similar. Three types of peaks were distinguished on the basis of their width at half-height: T (<16 ms), C (between 16 and 180 ms), and H peaks (>180 ms). T peaks were very rarely observed (<1% in single-unit recordings). H peaks were observed in 7-16% of the single-unit CCHs, and C peaks in 6-16%, depending on the stimulus used. C and H peaks were observed more often when the receptive fields were overlapping or distant by <2 degrees. To test for the presence of synchronization between neurons in areas V1 and V2, we measured the position of the CCH peak with respect to the origin of the time axis of the CCH. Only in the case of a few T peaks did we find displaced peaks, indicating a possible drive of the V2 neuron by the simultaneously recorded V1 cell. All the other peaks were either centered on the origin or overlapped the origin of time with their upper halves. Thus similarly to what has been reported for the cat, neurons belonging to different cortical areas in the monkey tend to synchronize the time of emission of their action potentials with three different levels of temporal precision. For peaks calculated from flashed stimuli, we compared the peak position with the difference between latencies of V1 and V2 neurons. There was a clear correlation for single-unit pairs in the case of C peaks. Thus the position of a C peak on the time axis appears to reflect the order of visual activation of the correlated neurons. The coupling strength for H peaks was smaller during visual drive compared with spontaneous activity. On the contrary, C peaks were seen more often and were stronger during visual stimulation than during spontaneous activity. This suggests that C-type synchronization is associated with the processing of visual information. The origin of synchronized activity in a serially organized system is discussed.  (+info)

Visual fields refer to the total area in which objects can be seen while keeping the eyes focused on a central point. It is the entire area that can be observed using peripheral (side) vision while the eye gazes at a fixed point. A visual field test is used to detect blind spots or gaps (scotomas) in a person's vision, which could indicate various medical conditions such as glaucoma, retinal damage, optic nerve disease, brain tumors, or strokes. The test measures both the central and peripheral vision and maps the entire area that can be seen when focusing on a single point.

A visual field test is a method used to measure an individual's entire scope of vision, which includes what can be seen straight ahead and in peripheral (or side) vision. During the test, the person being tested is asked to focus on a central point while gradually identifying the appearance of objects moving into their peripheral vision. The visual field test helps detect blind spots (scotomas) or gaps in the visual field, which can be caused by various conditions such as glaucoma, brain injury, optic nerve damage, or retinal disorders. It's an essential tool for diagnosing and monitoring eye-related diseases and conditions.

Vision disorders refer to a wide range of conditions that affect the visual system and result in various symptoms, such as blurry vision, double vision, distorted vision, impaired depth perception, and difficulty with visual tracking or focusing. These disorders can be categorized into several types, including:

1. Refractive errors: These occur when the shape of the eye prevents light from focusing directly on the retina, resulting in blurry vision. Examples include myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia (age-related loss of near vision).
2. Strabismus: Also known as crossed eyes or walleye, strabismus is a misalignment of the eyes where they point in different directions, which can lead to double vision or loss of depth perception.
3. Amblyopia: Often called lazy eye, amblyopia is a condition where one eye has reduced vision due to lack of proper visual development during childhood. It may be caused by strabismus, refractive errors, or other factors that interfere with normal visual development.
4. Accommodative disorders: These involve problems with the focusing ability of the eyes, such as convergence insufficiency (difficulty focusing on close objects) and accommodative dysfunction (inability to maintain clear vision at different distances).
5. Binocular vision disorders: These affect how the eyes work together as a team, leading to issues like poor depth perception, eye strain, and headaches. Examples include convergence insufficiency, divergence excess, and suppression.
6. Ocular motility disorders: These involve problems with eye movement, such as nystagmus (involuntary eye movements), strabismus, or restricted extraocular muscle function.
7. Visual processing disorders: These affect the brain's ability to interpret and make sense of visual information, even when the eyes themselves are healthy. Symptoms may include difficulty with reading, recognizing shapes and objects, and understanding spatial relationships.
8. Low vision: This term refers to significant visual impairment that cannot be fully corrected with glasses, contact lenses, medication, or surgery. It includes conditions like macular degeneration, diabetic retinopathy, glaucoma, and cataracts.
9. Blindness: Complete loss of sight in both eyes, which can be caused by various factors such as injury, disease, or genetic conditions.

Visual acuity is a measure of the sharpness or clarity of vision. It is usually tested by reading an eye chart from a specific distance, such as 20 feet (6 meters). The standard eye chart used for this purpose is called the Snellen chart, which contains rows of letters that decrease in size as you read down the chart.

Visual acuity is typically expressed as a fraction, with the numerator representing the testing distance and the denominator indicating the smallest line of type that can be read clearly. For example, if a person can read the line on the eye chart that corresponds to a visual acuity of 20/20, it means they have normal vision at 20 feet. If their visual acuity is 20/40, it means they must be as close as 20 feet to see what someone with normal vision can see at 40 feet.

It's important to note that visual acuity is just one aspect of overall vision and does not necessarily reflect other important factors such as peripheral vision, depth perception, color vision, or contrast sensitivity.

The visual cortex is the part of the brain that processes visual information. It is located in the occipital lobe, which is at the back of the brain. The visual cortex is responsible for receiving and interpreting signals from the retina, which are then transmitted through the optic nerve and optic tract.

The visual cortex contains several areas that are involved in different aspects of visual processing, such as identifying shapes, colors, and movements. These areas work together to help us recognize and understand what we see. Damage to the visual cortex can result in various visual impairments, such as blindness or difficulty with visual perception.

Visual perception refers to the ability to interpret and organize information that comes from our eyes to recognize and understand what we are seeing. It involves several cognitive processes such as pattern recognition, size estimation, movement detection, and depth perception. Visual perception allows us to identify objects, navigate through space, and interact with our environment. Deficits in visual perception can lead to learning difficulties and disabilities.

Evoked potentials, visual, also known as visually evoked potentials (VEPs), are electrical responses recorded from the brain following the presentation of a visual stimulus. These responses are typically measured using electroencephalography (EEG) and can provide information about the functioning of the visual pathways in the brain.

There are several types of VEPs, including pattern-reversal VEPs and flash VEPs. Pattern-reversal VEPs are elicited by presenting alternating checkerboard patterns, while flash VEPs are elicited by flashing a light. The responses are typically analyzed in terms of their latency (the time it takes for the response to occur) and amplitude (the size of the response).

VEPs are often used in clinical settings to help diagnose and monitor conditions that affect the visual system, such as multiple sclerosis, optic neuritis, and brainstem tumors. They can also be used in research to study the neural mechanisms underlying visual perception.

Visual pathways, also known as the visual system or the optic pathway, refer to the series of specialized neurons in the nervous system that transmit visual information from the eyes to the brain. This complex network includes the retina, optic nerve, optic chiasma, optic tract, lateral geniculate nucleus, pulvinar, and the primary and secondary visual cortices located in the occipital lobe of the brain.

The process begins when light enters the eye and strikes the photoreceptor cells (rods and cones) in the retina, converting the light energy into electrical signals. These signals are then transmitted to bipolar cells and subsequently to ganglion cells, whose axons form the optic nerve. The fibers from each eye's nasal hemiretina cross at the optic chiasma, while those from the temporal hemiretina continue without crossing. This results in the formation of the optic tract, which carries visual information from both eyes to the opposite side of the brain.

The majority of fibers in the optic tract synapse with neurons in the lateral geniculate nucleus (LGN), a part of the thalamus. The LGN sends this information to the primary visual cortex, also known as V1 or Brodmann area 17, located in the occipital lobe. Here, simple features like lines and edges are initially processed. Further processing occurs in secondary (V2) and tertiary (V3-V5) visual cortices, where more complex features such as shape, motion, and depth are analyzed. Ultimately, this information is integrated to form our perception of the visual world.

Hemianopsia is a medical term that refers to a loss of vision in half of the visual field in one or both eyes. It can be either homonymous (the same side in both eyes) or heteronymous (different sides in each eye). Hemianopsia usually results from damage to the optic radiations or occipital cortex in the brain, often due to stroke, trauma, tumor, or other neurological conditions. It can significantly impact a person's daily functioning and may require visual rehabilitation to help compensate for the vision loss.

A scotoma is a blind spot or area of reduced vision within the visual field. It's often surrounded by an area of less distinct vision and can be caused by various conditions such as eye diseases, neurological disorders, or brain injuries. A scotoma may be temporary or permanent, depending on its underlying cause.

There are different types of scotomas, including:

1. Central scotoma - a blind spot in the center of the visual field, often associated with conditions like age-related macular degeneration and diabetic retinopathy.
2. Paracentral scotoma - a blind spot located slightly away from the center of the visual field, which can be caused by optic neuritis or other optic nerve disorders.
3. Peripheral scotoma - a blind spot in the peripheral vision, often associated with retinal diseases like retinitis pigmentosa.
4. Absolute scotoma - a complete loss of vision in a specific area of the visual field.
5. Relative scotoma - a partial loss of vision in which some details can still be perceived, but not as clearly or vividly as in normal vision.

It is essential to consult an eye care professional if you experience any changes in your vision or notice a scotoma, as early detection and treatment can help prevent further vision loss.

Glaucoma is a group of eye conditions that damage the optic nerve, often caused by an abnormally high pressure in the eye (intraocular pressure). This damage can lead to permanent vision loss or even blindness if left untreated. The most common type is open-angle glaucoma, which has no warning signs and progresses slowly. Angle-closure glaucoma, on the other hand, can cause sudden eye pain, redness, nausea, and vomiting, as well as rapid vision loss. Other less common types of glaucoma also exist. While there is no cure for glaucoma, early detection and treatment can help slow or prevent further vision loss.

Open-angle glaucoma is a chronic, progressive type of glaucoma characterized by the gradual loss of optic nerve fibers and resulting in visual field defects. It is called "open-angle" because the angle where the iris meets the cornea (trabecular meshwork) appears to be normal and open on examination. The exact cause of this condition is not fully understood, but it is associated with increased resistance to the outflow of aqueous humor within the trabecular meshwork, leading to an increase in intraocular pressure (IOP). This elevated IOP can cause damage to the optic nerve and result in vision loss.

The onset of open-angle glaucoma is often asymptomatic, making regular comprehensive eye examinations crucial for early detection and management. Treatment typically involves lowering IOP using medications, laser therapy, or surgery to prevent further optic nerve damage and preserve vision.

Photic stimulation is a medical term that refers to the exposure of the eyes to light, specifically repetitive pulses of light, which is used as a method in various research and clinical settings. In neuroscience, it's often used in studies related to vision, circadian rhythms, and brain function.

In a clinical context, photic stimulation is sometimes used in the diagnosis of certain medical conditions such as seizure disorders (like epilepsy). By observing the response of the brain to this light stimulus, doctors can gain valuable insights into the functioning of the brain and the presence of any neurological disorders.

However, it's important to note that photic stimulation should be conducted under the supervision of a trained healthcare professional, as improper use can potentially trigger seizures in individuals who are susceptible to them.

Optic nerve diseases refer to a group of conditions that affect the optic nerve, which transmits visual information from the eye to the brain. These diseases can cause various symptoms such as vision loss, decreased visual acuity, changes in color vision, and visual field defects. Examples of optic nerve diseases include optic neuritis (inflammation of the optic nerve), glaucoma (damage to the optic nerve due to high eye pressure), optic nerve damage from trauma or injury, ischemic optic neuropathy (lack of blood flow to the optic nerve), and optic nerve tumors. Treatment for optic nerve diseases varies depending on the specific condition and may include medications, surgery, or lifestyle changes.

Visual pattern recognition is the ability to identify and interpret patterns in visual information. In a medical context, it often refers to the process by which healthcare professionals recognize and diagnose medical conditions based on visible signs or symptoms. This can involve recognizing the characteristic appearance of a rash, wound, or other physical feature associated with a particular disease or condition. It may also involve recognizing patterns in medical images such as X-rays, CT scans, or MRIs.

In the field of radiology, for example, visual pattern recognition is a critical skill. Radiologists are trained to recognize the typical appearances of various diseases and conditions in medical images. This allows them to make accurate diagnoses based on the patterns they see. Similarly, dermatologists use visual pattern recognition to identify skin abnormalities and diseases based on the appearance of rashes, lesions, or other skin changes.

Overall, visual pattern recognition is an essential skill in many areas of medicine, allowing healthcare professionals to quickly and accurately diagnose medical conditions based on visible signs and symptoms.

Ocular hypertension is a medical condition characterized by elevated pressure within the eye (intraocular pressure or IOP), which is higher than normal but not necessarily high enough to cause any visible damage to the optic nerve or visual field loss. It serves as a significant risk factor for developing glaucoma, a sight-threatening disease.

The normal range of intraocular pressure is typically between 10-21 mmHg (millimeters of mercury). Ocular hypertension is often defined as an IOP consistently above 21 mmHg, although some studies suggest that even pressures between 22-30 mmHg may not cause damage in all individuals. Regular monitoring and follow-up with an ophthalmologist are essential for people diagnosed with ocular hypertension to ensure early detection and management of any potential glaucomatous changes. Treatment options include medications, laser therapy, or surgery to lower the IOP and reduce the risk of glaucoma onset.

Ocular vision refers to the ability to process and interpret visual information that is received by the eyes. This includes the ability to see clearly and make sense of the shapes, colors, and movements of objects in the environment. The ocular system, which includes the eye and related structures such as the optic nerve and visual cortex of the brain, works together to enable vision.

There are several components of ocular vision, including:

* Visual acuity: the clarity or sharpness of vision
* Field of vision: the extent of the visual world that is visible at any given moment
* Color vision: the ability to distinguish different colors
* Depth perception: the ability to judge the distance of objects in three-dimensional space
* Contrast sensitivity: the ability to distinguish an object from its background based on differences in contrast

Disorders of ocular vision can include refractive errors such as nearsightedness or farsightedness, as well as more serious conditions such as cataracts, glaucoma, and macular degeneration. These conditions can affect one or more aspects of ocular vision and may require medical treatment to prevent further vision loss.

Vision tests are a series of procedures used to assess various aspects of the visual system, including visual acuity, accommodation, convergence, divergence, stereopsis, color vision, and peripheral vision. These tests help healthcare professionals diagnose and manage vision disorders, such as nearsightedness, farsightedness, astigmatism, amblyopia, strabismus, and eye diseases like glaucoma, cataracts, and macular degeneration. Common vision tests include:

1. Visual acuity test (Snellen chart or letter chart): Measures the sharpness of a person's vision at different distances.
2. Refraction test: Determines the correct lens prescription for glasses or contact lenses by assessing how light is bent as it passes through the eye.
3. Color vision test: Evaluates the ability to distinguish between different colors and color combinations, often using pseudoisochromatic plates or Ishihara tests.
4. Stereopsis test: Assesses depth perception and binocular vision by presenting separate images to each eye that, when combined, create a three-dimensional effect.
5. Cover test: Examines eye alignment and the presence of strabismus (crossed eyes or turned eyes) by covering and uncovering each eye while observing eye movements.
6. Ocular motility test: Assesses the ability to move the eyes in various directions and coordinate both eyes during tracking and convergence/divergence movements.
7. Accommodation test: Evaluates the ability to focus on objects at different distances by using lenses, prisms, or dynamic retinoscopy.
8. Pupillary response test: Examines the size and reaction of the pupils to light and near objects.
9. Visual field test: Measures the peripheral (side) vision using automated perimetry or manual confrontation techniques.
10. Slit-lamp examination: Inspects the structures of the front part of the eye, such as the cornea, iris, lens, and anterior chamber, using a specialized microscope.

These tests are typically performed by optometrists, ophthalmologists, or other vision care professionals during routine eye examinations or when visual symptoms are present.

The optic disk, also known as the optic nerve head, is the point where the optic nerve fibers exit the eye and transmit visual information to the brain. It appears as a pale, circular area in the back of the eye, near the center of the retina. The optic disk has no photoreceptor cells (rods and cones), so it is insensitive to light. It is an important structure to observe during eye examinations because changes in its appearance can indicate various ocular diseases or conditions, such as glaucoma, optic neuritis, or papilledema.

Contrast sensitivity is a measure of the ability to distinguish between an object and its background based on differences in contrast, rather than differences in luminance. Contrast refers to the difference in light intensity between an object and its immediate surroundings. Contrast sensitivity is typically measured using specially designed charts that have patterns of parallel lines with varying widths and contrast levels.

In clinical settings, contrast sensitivity is often assessed as part of a comprehensive visual examination. Poor contrast sensitivity can affect a person's ability to perform tasks such as reading, driving, or distinguishing objects from their background, especially in low-light conditions. Reduced contrast sensitivity is a common symptom of various eye conditions, including cataracts, glaucoma, and age-related macular degeneration.

Intraocular pressure (IOP) is the fluid pressure within the eye, specifically within the anterior chamber, which is the space between the cornea and the iris. It is measured in millimeters of mercury (mmHg). The aqueous humor, a clear fluid that fills the anterior chamber, is constantly produced and drained, maintaining a balance that determines the IOP. Normal IOP ranges from 10-21 mmHg, with average values around 15-16 mmHg. Elevated IOP is a key risk factor for glaucoma, a group of eye conditions that can lead to optic nerve damage and vision loss if not treated promptly and effectively. Regular monitoring of IOP is essential in diagnosing and managing glaucoma and other ocular health issues.

Sensory thresholds are the minimum levels of stimulation that are required to produce a sensation in an individual, as determined through psychophysical testing. These tests measure the point at which a person can just barely detect the presence of a stimulus, such as a sound, light, touch, or smell.

There are two types of sensory thresholds: absolute and difference. Absolute threshold is the minimum level of intensity required to detect a stimulus 50% of the time. Difference threshold, also known as just noticeable difference (JND), is the smallest change in intensity that can be detected between two stimuli.

Sensory thresholds can vary between individuals and are influenced by factors such as age, attention, motivation, and expectations. They are often used in clinical settings to assess sensory function and diagnose conditions such as hearing or vision loss.

Ocular fixation is a term used in ophthalmology and optometry to refer to the ability of the eyes to maintain steady gaze or visual focus on an object. It involves the coordinated movement of the extraocular muscles that control eye movements, allowing for clear and stable vision.

In medical terminology, fixation specifically refers to the state in which the eyes are aligned and focused on a single point in space. This is important for maintaining visual perception and preventing blurring or double vision. Ocular fixation can be affected by various factors such as muscle weakness, nerve damage, or visual processing disorders.

Assessment of ocular fixation is often used in eye examinations to evaluate visual acuity, eye alignment, and muscle function. Abnormalities in fixation may indicate the presence of underlying eye conditions or developmental delays that require further investigation and treatment.

Binocular vision refers to the ability to use both eyes together to create a single, three-dimensional image of our surroundings. This is achieved through a process called binocular fusion, where the images from each eye are aligned and combined in the brain to form a unified perception.

The term "binocular vision" specifically refers to the way that our visual system integrates information from both eyes to create depth perception and enhance visual clarity. When we view an object with both eyes, they focus on the same point in space and send slightly different images to the brain due to their slightly different positions. The brain then combines these images to create a single, three-dimensional image that allows us to perceive depth and distance.

Binocular vision is important for many everyday activities, such as driving, reading, and playing sports. Disorders of binocular vision can lead to symptoms such as double vision, eye strain, and difficulty with depth perception.

Motion perception is the ability to interpret and understand the movement of objects in our environment. It is a complex process that involves multiple areas of the brain and the visual system. In medical terms, motion perception refers to the specific function of the visual system to detect and analyze the movement of visual stimuli. This allows us to perceive and respond to moving objects in our environment, which is crucial for activities such as driving, sports, and even maintaining balance. Disorders in motion perception can lead to conditions like motion sickness or difficulty with depth perception.

In a medical or psychological context, attention is the cognitive process of selectively concentrating on certain aspects of the environment while ignoring other things. It involves focusing mental resources on specific stimuli, sensory inputs, or internal thoughts while blocking out irrelevant distractions. Attention can be divided into different types, including:

1. Sustained attention: The ability to maintain focus on a task or stimulus over time.
2. Selective attention: The ability to concentrate on relevant stimuli while ignoring irrelevant ones.
3. Divided attention: The capacity to pay attention to multiple tasks or stimuli simultaneously.
4. Alternating attention: The skill of shifting focus between different tasks or stimuli as needed.

Deficits in attention are common symptoms of various neurological and psychiatric conditions, such as ADHD, dementia, depression, and anxiety disorders. Assessment of attention is an essential part of neuropsychological evaluations and can be measured using various tests and tasks.

Eye movements, also known as ocular motility, refer to the voluntary or involuntary motion of the eyes that allows for visual exploration of our environment. There are several types of eye movements, including:

1. Saccades: rapid, ballistic movements that quickly shift the gaze from one point to another.
2. Pursuits: smooth, slow movements that allow the eyes to follow a moving object.
3. Vergences: coordinated movements of both eyes in opposite directions, usually in response to a three-dimensional stimulus.
4. Vestibulo-ocular reflex (VOR): automatic eye movements that help stabilize the gaze during head movement.
5. Optokinetic nystagmus (OKN): rhythmic eye movements that occur in response to large moving visual patterns, such as when looking out of a moving vehicle.

Abnormalities in eye movements can indicate neurological or ophthalmological disorders and are often assessed during clinical examinations.

Space perception, in the context of neuroscience and psychology, refers to the ability to perceive and understand the spatial arrangement of objects and their relationship to oneself. It involves integrating various sensory inputs such as visual, auditory, tactile, and proprioceptive information to create a coherent three-dimensional representation of our environment.

This cognitive process enables us to judge distances, sizes, shapes, and movements of objects around us. It also helps us navigate through space, reach for objects, avoid obstacles, and maintain balance. Disorders in space perception can lead to difficulties in performing everyday activities and may be associated with neurological conditions such as stroke, brain injury, or neurodevelopmental disorders like autism.

The optic chiasm is a structure in the brain where the optic nerves from each eye meet and cross. This allows for the integration of visual information from both eyes into the brain's visual cortex, creating a single, combined image of the visual world. The optic chiasm plays an important role in the processing of visual information and helps to facilitate depth perception and other complex visual tasks. Damage to the optic chiasm can result in various visual field deficits, such as bitemporal hemianopsia, where there is a loss of vision in the outer halves (temporal fields) of both eyes' visual fields.

Vigabatrin is an anticonvulsant medication used to treat certain types of seizures in adults and children. It works by reducing the abnormal excitement in the brain. The medical definition of Vigabatrin is: a irreversible inhibitor of GABA transaminase, which results in increased levels of gamma-aminobutyric acid (GABA) in the central nervous system. This medication is used as an adjunctive treatment for complex partial seizures and is available in oral form for administration.

It's important to note that Vigabatrin can cause serious side effects, including permanent vision loss, and its use should be closely monitored by a healthcare professional. It is also classified as a pregnancy category C medication, which means it may harm an unborn baby and should only be used during pregnancy if the potential benefit justifies the potential risk to the fetus.

The retina is the innermost, light-sensitive layer of tissue in the eye of many vertebrates and some cephalopods. It receives light that has been focused by the cornea and lens, converts it into neural signals, and sends these to the brain via the optic nerve. The retina contains several types of photoreceptor cells including rods (which handle vision in low light) and cones (which are active in bright light and are capable of color vision).

In medical terms, any pathological changes or diseases affecting the retinal structure and function can lead to visual impairment or blindness. Examples include age-related macular degeneration, diabetic retinopathy, retinal detachment, and retinitis pigmentosa among others.

Psychophysics is not a medical term per se, but rather a subfield of psychology and neuroscience that studies the relationship between physical stimuli and the sensations and perceptions they produce. It involves the quantitative investigation of psychological functions, such as how brightness or loudness is perceived relative to the physical intensity of light or sound.

In medical contexts, psychophysical methods may be used in research or clinical settings to understand how patients with neurological conditions or sensory impairments perceive and respond to different stimuli. This information can inform diagnostic assessments, treatment planning, and rehabilitation strategies.

Electroretinography (ERG) is a medical test used to evaluate the functioning of the retina, which is the light-sensitive tissue located at the back of the eye. The test measures the electrical responses of the retina to light stimulation.

During the procedure, a special contact lens or electrode is placed on the surface of the eye to record the electrical activity generated by the retina's light-sensitive cells (rods and cones) and other cells in the retina. The test typically involves presenting different levels of flashes of light to the eye while the electrical responses are recorded.

The resulting ERG waveform provides information about the overall health and function of the retina, including the condition of the photoreceptors, the integrity of the inner retinal layers, and the health of the retinal ganglion cells. This test is often used to diagnose and monitor various retinal disorders, such as retinitis pigmentosa, macular degeneration, and diabetic retinopathy.

Reaction time, in the context of medicine and physiology, refers to the time period between the presentation of a stimulus and the subsequent initiation of a response. This complex process involves the central nervous system, particularly the brain, which perceives the stimulus, processes it, and then sends signals to the appropriate muscles or glands to react.

There are different types of reaction times, including simple reaction time (responding to a single, expected stimulus) and choice reaction time (choosing an appropriate response from multiple possibilities). These measures can be used in clinical settings to assess various aspects of neurological function, such as cognitive processing speed, motor control, and alertness.

However, it is important to note that reaction times can be influenced by several factors, including age, fatigue, attention, and the use of certain medications or substances.

Brain mapping is a broad term that refers to the techniques used to understand the structure and function of the brain. It involves creating maps of the various cognitive, emotional, and behavioral processes in the brain by correlating these processes with physical locations or activities within the nervous system. Brain mapping can be accomplished through a variety of methods, including functional magnetic resonance imaging (fMRI), positron emission tomography (PET) scans, electroencephalography (EEG), and others. These techniques allow researchers to observe which areas of the brain are active during different tasks or thoughts, helping to shed light on how the brain processes information and contributes to our experiences and behaviors. Brain mapping is an important area of research in neuroscience, with potential applications in the diagnosis and treatment of neurological and psychiatric disorders.

Retinal Ganglion Cells (RGCs) are a type of neuron located in the innermost layer of the retina, the light-sensitive tissue at the back of the eye. These cells receive visual information from photoreceptors (rods and cones) via intermediate cells called bipolar cells. RGCs then send this visual information through their long axons to form the optic nerve, which transmits the signals to the brain for processing and interpretation as vision.

There are several types of RGCs, each with distinct morphological and functional characteristics. Some RGCs are specialized in detecting specific features of the visual scene, such as motion, contrast, color, or brightness. The diversity of RGCs allows for a rich and complex representation of the visual world in the brain.

Damage to RGCs can lead to various visual impairments, including loss of vision, reduced visual acuity, and altered visual fields. Conditions associated with RGC damage or degeneration include glaucoma, optic neuritis, ischemic optic neuropathy, and some inherited retinal diseases.

Blindness is a condition of complete or near-complete vision loss. It can be caused by various factors such as eye diseases, injuries, or birth defects. Total blindness means that a person cannot see anything at all, while near-complete blindness refers to having only light perception or the ability to perceive the direction of light, but not able to discern shapes or forms. Legal blindness is a term used to define a certain level of visual impairment that qualifies an individual for government assistance and benefits; it usually means best corrected visual acuity of 20/200 or worse in the better eye, or a visual field no greater than 20 degrees in diameter.

Optical coherence tomography (OCT) is a non-invasive imaging technique that uses low-coherence light to capture high-resolution cross-sectional images of biological tissues, particularly the retina and other ocular structures. OCT works by measuring the echo time delay of light scattered back from different depths within the tissue, creating a detailed map of the tissue's structure. This technique is widely used in ophthalmology to diagnose and monitor various eye conditions such as macular degeneration, diabetic retinopathy, and glaucoma.

Diagnostic techniques in ophthalmology refer to the various methods and tests used by eye specialists (ophthalmologists) to examine, evaluate, and diagnose conditions related to the eyes and visual system. Here are some commonly used diagnostic techniques:

1. Visual Acuity Testing: This is a basic test to measure the sharpness of a person's vision. It typically involves reading letters or numbers from an eye chart at a specific distance.
2. Refraction Test: This test helps determine the correct lens prescription for glasses or contact lenses by measuring how light is bent as it passes through the cornea and lens.
3. Slit Lamp Examination: A slit lamp is a microscope that allows an ophthalmologist to examine the structures of the eye, including the cornea, iris, lens, and retina, in great detail.
4. Tonometry: This test measures the pressure inside the eye (intraocular pressure) to detect conditions like glaucoma. Common methods include applanation tonometry and non-contact tonometry.
5. Retinal Imaging: Several techniques are used to capture images of the retina, including fundus photography, fluorescein angiography, and optical coherence tomography (OCT). These tests help diagnose conditions like macular degeneration, diabetic retinopathy, and retinal detachments.
6. Color Vision Testing: This test evaluates a person's ability to distinguish between different colors, which can help detect color vision deficiencies or neurological disorders affecting the visual pathway.
7. Visual Field Testing: This test measures a person's peripheral (or side) vision and can help diagnose conditions like glaucoma, optic nerve damage, or brain injuries.
8. Pupillary Reactions Tests: These tests evaluate how the pupils respond to light and near objects, which can provide information about the condition of the eye's internal structures and the nervous system.
9. Ocular Motility Testing: This test assesses eye movements and alignment, helping diagnose conditions like strabismus (crossed eyes) or nystagmus (involuntary eye movement).
10. Corneal Topography: This non-invasive imaging technique maps the curvature of the cornea, which can help detect irregularities, assess the fit of contact lenses, and plan refractive surgery procedures.

Monocular vision refers to the ability to see and process visual information using only one eye. It is the type of vision that an individual has when they are using only one eye to look at something, while the other eye may be covered or not functioning. This can be contrasted with binocular vision, which involves the use of both eyes working together to provide depth perception and a single, combined visual field.

Monocular vision is important for tasks that only require the use of one eye, such as when looking through a microscope or using a telescope. However, it does not provide the same level of depth perception and spatial awareness as binocular vision. In some cases, individuals may have reduced visual acuity or other visual impairments in one eye, leading to limited monocular vision in that eye. It is important for individuals with monocular vision to have regular eye exams to monitor their eye health and ensure that any visual impairments are detected and treated promptly.

The fovea centralis, also known as the macula lutea, is a small pit or depression located in the center of the retina, an light-sensitive tissue at the back of the eye. It is responsible for sharp, detailed vision (central vision) and color perception. The fovea contains only cones, the photoreceptor cells that are responsible for color vision and high visual acuity. It has a higher concentration of cones than any other area in the retina, allowing it to provide the greatest detail and color discrimination. The center of the fovea is called the foveola, which contains the highest density of cones and is avascular, meaning it lacks blood vessels to avoid interfering with the light passing through to the photoreceptor cells.

Retinitis pigmentosa (RP) is a group of rare, genetic disorders that involve a breakdown and loss of cells in the retina - a light-sensitive tissue located at the back of the eye. The retina converts light into electrical signals which are then sent to the brain and interpreted as visual images.

In RP, the cells that detect light (rods and cones) degenerate more slowly than other cells in the retina, leading to a progressive loss of vision. Symptoms typically begin in childhood with night blindness (difficulty seeing in low light), followed by a gradual narrowing of the visual field (tunnel vision). Over time, this can lead to significant vision loss and even blindness.

The condition is usually inherited and there are several different genes that have been associated with RP. The diagnosis is typically made based on a combination of genetic testing, family history, and clinical examination. Currently, there is no cure for RP, but researchers are actively working to develop new treatments that may help slow or stop the progression of the disease.

Functional laterality, in a medical context, refers to the preferential use or performance of one side of the body over the other for specific functions. This is often demonstrated in hand dominance, where an individual may be right-handed or left-handed, meaning they primarily use their right or left hand for tasks such as writing, eating, or throwing.

However, functional laterality can also apply to other bodily functions and structures, including the eyes (ocular dominance), ears (auditory dominance), or legs. It's important to note that functional laterality is not a strict binary concept; some individuals may exhibit mixed dominance or no strong preference for one side over the other.

In clinical settings, assessing functional laterality can be useful in diagnosing and treating various neurological conditions, such as stroke or traumatic brain injury, where understanding any resulting lateralized impairments can inform rehabilitation strategies.

Nerve fibers are specialized structures that constitute the long, slender processes (axons) of neurons (nerve cells). They are responsible for conducting electrical impulses, known as action potentials, away from the cell body and transmitting them to other neurons or effector organs such as muscles and glands. Nerve fibers are often surrounded by supportive cells called glial cells and are grouped together to form nerve bundles or nerves. These fibers can be myelinated (covered with a fatty insulating sheath called myelin) or unmyelinated, which influences the speed of impulse transmission.

Electromagnetic fields (EMFs) are invisible forces that result from the interaction between electrically charged objects. They are created by natural phenomena, such as the Earth's magnetic field, as well as by human-made sources, such as power lines, electrical appliances, and wireless communication devices.

EMFs are characterized by their frequency and strength, which determine their potential biological effects. Low-frequency EMFs, such as those produced by power lines and household appliances, have frequencies in the range of 0 to 300 Hz. High-frequency EMFs, such as those produced by wireless communication devices like cell phones and Wi-Fi routers, have frequencies in the range of 100 kHz to 300 GHz.

Exposure to EMFs has been linked to a variety of health effects, including increased risk of cancer, reproductive problems, neurological disorders, and oxidative stress. However, more research is needed to fully understand the potential health risks associated with exposure to EMFs and to establish safe exposure limits.

Low vision is a term used to describe significant visual impairment that cannot be corrected with standard glasses, contact lenses, medication or surgery. It is typically defined as visual acuity of less than 20/70 in the better-seeing eye after best correction, or a visual field of less than 20 degrees in the better-seeing eye.

People with low vision may have difficulty performing everyday tasks such as reading, recognizing faces, watching television, driving, or simply navigating their environment. They may also experience symptoms such as sensitivity to light, glare, or contrast, and may benefit from the use of visual aids, assistive devices, and rehabilitation services to help them maximize their remaining vision and maintain their independence.

Low vision can result from a variety of causes, including eye diseases such as macular degeneration, diabetic retinopathy, glaucoma, or cataracts, as well as congenital or inherited conditions, brain injuries, or aging. It is important for individuals with low vision to receive regular eye examinations and consult with a low vision specialist to determine the best course of treatment and management.

Medical Definition:

Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic imaging technique that uses a strong magnetic field and radio waves to create detailed cross-sectional or three-dimensional images of the internal structures of the body. The patient lies within a large, cylindrical magnet, and the scanner detects changes in the direction of the magnetic field caused by protons in the body. These changes are then converted into detailed images that help medical professionals to diagnose and monitor various medical conditions, such as tumors, injuries, or diseases affecting the brain, spinal cord, heart, blood vessels, joints, and other internal organs. MRI does not use radiation like computed tomography (CT) scans.

Ischemic optic neuropathy (ION) is a medical condition that refers to the damage or death of the optic nerve due to insufficient blood supply. The optic nerve is responsible for transmitting visual information from the eye to the brain.

In ION, the blood vessels that supply the optic nerve become blocked or narrowed, leading to decreased blood flow and oxygen delivery to the nerve fibers. This results in inflammation, swelling, and ultimately, damage to the optic nerve. The damage can cause sudden, painless vision loss, often noticed upon waking up in the morning.

There are two types of ION: anterior ischemic optic neuropathy (AION) and posterior ischemic optic neuropathy (PION). AION affects the front part of the optic nerve, while PION affects the back part of the nerve. AION is further classified into arteritic and non-arteritic types, depending on whether it is caused by giant cell arteritis or not.

Risk factors for ION include age (most commonly occurring in people over 50), hypertension, diabetes, smoking, sleep apnea, and other cardiovascular diseases. Treatment options depend on the type and cause of ION and may include controlling underlying medical conditions, administering corticosteroids, or undergoing surgical procedures to improve blood flow.

A saccade is a quick, rapid, and ballistic conjugate eye movement that shifts the point of fixation from one target to another. It helps in rapidly repositioning the fovea (the central part of the retina with the highest visual acuity) to focus on different targets of interest in the visual scene. Saccades are essential for efficient scanning and exploration of our environment, allowing us to direct our high-resolution vision towards various points of interest. They typically take only about 20-200 milliseconds to complete and can reach peak velocities of up to 500 degrees per second or more, depending on the amplitude of the movement. Saccades are a critical component of normal visual function and are often studied in fields such as ophthalmology, neurology, and neuroscience.

Psychomotor performance refers to the integration and coordination of mental processes (cognitive functions) with physical movements. It involves the ability to perform complex tasks that require both cognitive skills, such as thinking, remembering, and perceiving, and motor skills, such as gross and fine motor movements. Examples of psychomotor performances include driving a car, playing a musical instrument, or performing surgical procedures.

In a medical context, psychomotor performance is often used to assess an individual's ability to perform activities of daily living (ADLs) and instrumental activities of daily living (IADLs), such as bathing, dressing, cooking, cleaning, and managing medications. Deficits in psychomotor performance can be a sign of neurological or psychiatric disorders, such as dementia, Parkinson's disease, or depression.

Assessment of psychomotor performance may involve tests that measure reaction time, coordination, speed, precision, and accuracy of movements, as well as cognitive functions such as attention, memory, and problem-solving skills. These assessments can help healthcare professionals develop appropriate treatment plans and monitor the progression of diseases or the effectiveness of interventions.

Ophthalmoscopy is a medical examination technique used by healthcare professionals to observe the interior structures of the eye, including the retina, optic disc, and vitreous humor. This procedure typically involves using an ophthalmoscope, a handheld device that consists of a light and magnifying lenses. The healthcare provider looks through the ophthalmoscope and directly observes the internal structures of the eye by illuminating them.

There are several types of ophthalmoscopy, including direct ophthalmoscopy, indirect ophthalmoscopy, and slit-lamp biomicroscopy. Each type has its own advantages and disadvantages, and they may be used in different situations depending on the specific clinical situation and the information needed.

Ophthalmoscopy is an important diagnostic tool for detecting and monitoring a wide range of eye conditions, including diabetic retinopathy, glaucoma, age-related macular degeneration, and other retinal disorders. It can also provide valuable information about the overall health of the individual, as changes in the appearance of the retina or optic nerve may indicate the presence of systemic diseases such as hypertension or diabetes.

Ocular tonometry is a medical test used to measure the pressure inside the eye, also known as intraocular pressure (IOP). This test is an essential part of diagnosing and monitoring glaucoma, a group of eye conditions that can cause vision loss and blindness due to damage to the optic nerve from high IOP.

The most common method of ocular tonometry involves using a tonometer device that gently touches the front surface of the eye (cornea) with a small probe or prism. The device measures the amount of force required to flatten the cornea slightly, which correlates with the pressure inside the eye. Other methods of ocular tonometry include applanation tonometry, which uses a small amount of fluorescein dye and a blue light to measure the IOP, and rebound tonometry, which uses a lightweight probe that briefly touches the cornea and then bounces back to determine the IOP.

Regular ocular tonometry is important for detecting glaucoma early and preventing vision loss. It is typically performed during routine eye exams and may be recommended more frequently for individuals at higher risk of developing glaucoma, such as those with a family history of the condition or certain medical conditions like diabetes.

"Ocular physiological phenomena" is not a standardized medical term with a specific definition. However, I can provide some examples of ocular physiological phenomena, which refer to various normal functions and processes that occur in the eye. Here are a few examples:

1. Accommodation: The ability of the eye to change optical power to maintain a clear image or focus on an object as its distance varies. This is primarily achieved by changing the curvature of the lens through the action of the ciliary muscles.
2. Pupillary reflex: The automatic adjustment of the pupil's size in response to changes in light intensity. In bright light, the pupil constricts (miosis), while in dim light, it dilates (mydriasis). This reflex helps regulate the amount of light that enters the eye.
3. Tear production: The continuous secretion of tears by the lacrimal glands to keep the eyes moist and protected from dust, microorganisms, and other foreign particles.
4. Extraocular muscle function: The coordinated movement of the six extraocular muscles that control eyeball rotation and enable various gaze directions.
5. Color vision: The ability to perceive and distinguish different colors based on the sensitivity of photoreceptor cells (cones) in the retina to specific wavelengths of light.
6. Dark adaptation: The process by which the eyes adjust to low-light conditions, improving visual sensitivity primarily through changes in the rod photoreceptors' sensitivity and pupil dilation.
7. Light adaptation: The ability of the eye to adjust to different levels of illumination, mainly through alterations in pupil size and photoreceptor cell response.

These are just a few examples of ocular physiological phenomena. There are many more processes and functions that occur within the eye, contributing to our visual perception and overall eye health.

Perceptual disorders are conditions that affect the way a person perceives or interprets sensory information from their environment. These disorders can involve any of the senses, including sight, sound, touch, taste, and smell. They can cause a person to have difficulty recognizing, interpreting, or responding appropriately to sensory stimuli.

Perceptual disorders can result from damage to the brain or nervous system, such as from a head injury, stroke, or degenerative neurological condition. They can also be caused by certain mental health conditions, such as schizophrenia or severe depression.

Symptoms of perceptual disorders may include:

* Misinterpretations of sensory information, such as seeing things that are not there or hearing voices that are not present
* Difficulty recognizing familiar objects or people
* Problems with depth perception or spatial awareness
* Difficulty judging the size, shape, or distance of objects
* Trouble distinguishing between similar sounds or colors
* Impaired sense of smell or taste

Perceptual disorders can have a significant impact on a person's daily life and functioning. Treatment may involve medication, therapy, or rehabilitation to help the person better cope with their symptoms and improve their ability to interact with their environment.

Low tension glaucoma, also known as normal tension glaucoma, is a type of glaucoma characterized by optic nerve damage and visual field loss in the absence of consistently elevated intraocular pressure (IOP). In this form of glaucoma, the IOP typically remains within the statistically normal range, which is generally defined as below 21 mmHg. However, some individuals may have an IOP that is considered "low tension" for their specific optic nerve susceptibility.

The exact cause of low tension glaucoma remains unclear, but it is thought to involve factors such as impaired blood flow to the optic nerve, genetic predisposition, and sensitivity to minor fluctuations in IOP. People with low tension glaucoma may require close monitoring and management, including regular IOP checks, visual field testing, and sometimes the use of medications or surgical interventions to reduce the risk of further optic nerve damage and vision loss.

Retinal diseases refer to a group of conditions that affect the retina, which is the light-sensitive tissue located at the back of the eye. The retina is responsible for converting light into electrical signals that are sent to the brain and interpreted as visual images. Retinal diseases can cause vision loss or even blindness, depending on their severity and location in the retina.

Some common retinal diseases include:

1. Age-related macular degeneration (AMD): A progressive disease that affects the central part of the retina called the macula, causing blurred or distorted vision.
2. Diabetic retinopathy: A complication of diabetes that can damage the blood vessels in the retina, leading to vision loss.
3. Retinal detachment: A serious condition where the retina becomes separated from its underlying tissue, requiring immediate medical attention.
4. Macular edema: Swelling or thickening of the macula due to fluid accumulation, which can cause blurred vision.
5. Retinitis pigmentosa: A group of inherited eye disorders that affect the retina's ability to respond to light, causing progressive vision loss.
6. Macular hole: A small break in the macula that can cause distorted or blurry vision.
7. Retinal vein occlusion: Blockage of the retinal veins that can lead to bleeding, swelling, and potential vision loss.

Treatment for retinal diseases varies depending on the specific condition and its severity. Some treatments include medication, laser therapy, surgery, or a combination of these options. Regular eye exams are essential for early detection and treatment of retinal diseases.

Form perception, also known as shape perception, is not a term that has a specific medical definition. However, in the field of neuropsychology and sensory perception, form perception refers to the ability to recognize and interpret different shapes and forms of objects through visual processing. This ability is largely dependent on the integrity of the visual cortex and its ability to process and interpret information received from the retina.

Damage to certain areas of the brain, particularly in the occipital and parietal lobes, can result in deficits in form perception, leading to difficulties in recognizing and identifying objects based on their shape or form. This condition is known as visual agnosia and can be a symptom of various neurological disorders such as stroke, brain injury, or degenerative diseases like Alzheimer's disease.

The occipital lobe is the portion of the cerebral cortex that lies at the back of the brain (posteriorly) and is primarily involved in visual processing. It contains areas that are responsible for the interpretation and integration of visual stimuli, including color, form, movement, and recognition of objects. The occipital lobe is divided into several regions, such as the primary visual cortex (V1), secondary visual cortex (V2 to V5), and the visual association cortex, which work together to process different aspects of visual information. Damage to the occipital lobe can lead to various visual deficits, including blindness or partial loss of vision, known as a visual field cut.

In the context of medicine, "cues" generally refer to specific pieces of information or signals that can help healthcare professionals recognize and respond to a particular situation or condition. These cues can come in various forms, such as:

1. Physical examination findings: For example, a patient's abnormal heart rate or blood pressure reading during a physical exam may serve as a cue for the healthcare professional to investigate further.
2. Patient symptoms: A patient reporting chest pain, shortness of breath, or other concerning symptoms can act as a cue for a healthcare provider to consider potential diagnoses and develop an appropriate treatment plan.
3. Laboratory test results: Abnormal findings on laboratory tests, such as elevated blood glucose levels or abnormal liver function tests, may serve as cues for further evaluation and diagnosis.
4. Medical history information: A patient's medical history can provide valuable cues for healthcare professionals when assessing their current health status. For example, a history of smoking may increase the suspicion for chronic obstructive pulmonary disease (COPD) in a patient presenting with respiratory symptoms.
5. Behavioral or environmental cues: In some cases, behavioral or environmental factors can serve as cues for healthcare professionals to consider potential health risks. For instance, exposure to secondhand smoke or living in an area with high air pollution levels may increase the risk of developing respiratory conditions.

Overall, "cues" in a medical context are essential pieces of information that help healthcare professionals make informed decisions about patient care and treatment.

A pupil, in medical terms, refers to the circular opening in the center of the iris (the colored part of the eye) that allows light to enter and reach the retina. The size of the pupil can change involuntarily in response to light intensity and emotional state, as well as voluntarily through certain eye exercises or with the use of eye drops. Pupillary reactions are important in clinical examinations as they can provide valuable information about the nervous system's functioning, particularly the brainstem and cranial nerves II and III.

Eyeglasses are a medical device used to correct vision problems. Also known as spectacles, they consist of frames that hold one or more lenses through which a person looks to see clearly. The lenses may be made of glass or plastic and are designed to compensate for various visual impairments such as nearsightedness, farsightedness, astigmatism, or presbyopia. Eyeglasses can be custom-made to fit an individual's face and prescription, and they come in a variety of styles, colors, and materials. Some people wear eyeglasses all the time, while others may only need to wear them for certain activities such as reading or driving.

"Fundus Oculi" is a medical term that refers to the back part of the interior of the eye, including the optic disc, macula, fovea, retinal vasculature, and peripheral retina. It is the area where light is focused and then transmitted to the brain via the optic nerve, forming visual images. Examinations of the fundus oculi are crucial for detecting various eye conditions such as diabetic retinopathy, macular degeneration, glaucoma, and other retinal diseases. The examination is typically performed using an ophthalmoscope or a specialized camera called a retinal camera.

The superior colliculi are a pair of prominent eminences located on the dorsal surface of the midbrain, forming part of the tectum or roof of the midbrain. They play a crucial role in the integration and coordination of visual, auditory, and somatosensory information for the purpose of directing spatial attention and ocular movements. Essentially, they are involved in the reflexive orienting of the head and eyes towards novel or significant stimuli in the environment.

In a more detailed medical definition, the superior colliculi are two rounded, convex mounds of gray matter that are situated on the roof of the midbrain, specifically at the level of the rostral mesencephalic tegmentum. Each superior colliculus has a stratified laminated structure, consisting of several layers that process different types of sensory information and control specific motor outputs.

The superficial layers of the superior colliculi primarily receive and process visual input from the retina, lateral geniculate nucleus, and other visual areas in the brain. These layers are responsible for generating spatial maps of the visual field, which allow for the localization and identification of visual stimuli.

The intermediate and deep layers of the superior colliculi receive and process auditory and somatosensory information from various sources, including the inferior colliculus, medial geniculate nucleus, and ventral posterior nucleus of the thalamus. These layers are involved in the localization and identification of auditory and tactile stimuli, as well as the coordination of head and eye movements towards these stimuli.

The superior colliculi also contain a population of neurons called "motor command neurons" that directly control the muscles responsible for orienting the eyes, head, and body towards novel or significant sensory events. These motor command neurons are activated in response to specific patterns of activity in the sensory layers of the superior colliculus, allowing for the rapid and automatic orientation of attention and gaze towards salient stimuli.

In summary, the superior colliculi are a pair of structures located on the dorsal surface of the midbrain that play a critical role in the integration and coordination of visual, auditory, and somatosensory information for the purpose of orienting attention and gaze towards salient stimuli. They contain sensory layers that generate spatial maps of the environment, as well as motor command neurons that directly control the muscles responsible for orienting the eyes, head, and body.

Cortical blindness is a type of visual impairment that is caused by damage to the occipital cortex, which is the part of the brain responsible for processing visual information. This condition is also known as cerebral blindness or cerebral visual impairment.

In cortical blindness, the eyes are able to receive and transmit visual signals to the brain, but the brain is unable to interpret these signals correctly. As a result, the person may have difficulty recognizing objects, faces, or movements in their visual field. They may also experience hallucinations, such as seeing patterns or shapes that aren't really there.

Cortical blindness can be caused by a variety of factors, including stroke, trauma, brain tumors, infection, or hypoxia (lack of oxygen). In some cases, cortical blindness may be temporary and improve over time with treatment and rehabilitation. However, in other cases, the damage to the occipital cortex may be permanent, leading to a lifelong visual impairment.

It is important to note that cortical blindness is different from legal blindness, which is a term used to describe a severe visual impairment that cannot be corrected with glasses or contact lenses. In contrast, cortical blindness is a neurological condition that affects the brain's ability to process visual information, rather than a problem with the eyes themselves.

In a medical context, "orientation" typically refers to an individual's awareness and understanding of their personal identity, place, time, and situation. It is a critical component of cognitive functioning and mental status. Healthcare professionals often assess a person's orientation during clinical evaluations, using tests that inquire about their name, location, the current date, and the circumstances of their hospitalization or visit.

There are different levels of orientation:

1. Person (or self): The individual knows their own identity, including their name, age, and other personal details.
2. Place: The individual is aware of where they are, such as the name of the city, hospital, or healthcare facility.
3. Time: The individual can accurately state the current date, day of the week, month, and year.
4. Situation or event: The individual understands why they are in the healthcare setting, what happened leading to their hospitalization or visit, and the nature of any treatments or procedures they are undergoing.

Impairments in orientation can be indicative of various neurological or psychiatric conditions, such as delirium, dementia, or substance intoxication or withdrawal. It is essential for healthcare providers to monitor and address orientation issues to ensure appropriate diagnosis, treatment, and patient safety.

Fluorescein angiography is a medical diagnostic procedure used in ophthalmology to examine the blood flow in the retina and choroid, which are the inner layers of the eye. This test involves injecting a fluorescent dye, Fluorescein, into a patient's arm vein. As the dye reaches the blood vessels in the eye, a specialized camera takes rapid sequences of photographs to capture the dye's circulation through the retina and choroid.

The images produced by fluorescein angiography can help doctors identify any damage to the blood vessels, leakage, or abnormal growth of new blood vessels. This information is crucial in diagnosing and managing various eye conditions such as age-related macular degeneration, diabetic retinopathy, retinal vein occlusions, and inflammatory eye diseases.

It's important to note that while fluorescein angiography is a valuable diagnostic tool, it does carry some risks, including temporary side effects like nausea, vomiting, or allergic reactions to the dye. In rare cases, severe adverse reactions can occur, so patients should discuss these potential risks with their healthcare provider before undergoing the procedure.

The parietal lobe is a region of the brain that is located in the posterior part of the cerebral cortex, covering the upper and rear portions of the brain. It is involved in processing sensory information from the body, such as touch, temperature, and pain, as well as spatial awareness and perception, visual-spatial cognition, and the integration of different senses.

The parietal lobe can be divided into several functional areas, including the primary somatosensory cortex (which receives tactile information from the body), the secondary somatosensory cortex (which processes more complex tactile information), and the posterior parietal cortex (which is involved in spatial attention, perception, and motor planning).

Damage to the parietal lobe can result in various neurological symptoms, such as neglect of one side of the body, difficulty with spatial orientation, problems with hand-eye coordination, and impaired mathematical and language abilities.

I'm sorry for any confusion, but "photography" is not a term typically used in medical definitions. Photography refers to the art, application, or process of creating images by recording light or other electromagnetic radiation, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film.

If you're looking for a medical term related to imaging, there are several terms that might be relevant, such as:

1. Radiography: This is a technique using X-rays to visualize the internal structures of the body.
2. Ultrasonography: Also known as ultrasound, this is a diagnostic imaging technique using high-frequency sound waves to create images of the inside of the body.
3. Computed Tomography (CT): A type of imaging that uses X-rays to create detailed cross-sectional images of the body.
4. Magnetic Resonance Imaging (MRI): A type of imaging that uses magnetic fields and radio waves to create detailed images of the organs and tissues within the body.
5. Nuclear Medicine: This is a branch of medical imaging that uses small amounts of radioactive material to diagnose and treat diseases.

If you have any questions related to medical definitions or topics, feel free to ask!

The optic nerve, also known as the second cranial nerve, is the nerve that transmits visual information from the retina to the brain. It is composed of approximately one million nerve fibers that carry signals related to vision, such as light intensity and color, from the eye's photoreceptor cells (rods and cones) to the visual cortex in the brain. The optic nerve is responsible for carrying this visual information so that it can be processed and interpreted by the brain, allowing us to see and perceive our surroundings. Damage to the optic nerve can result in vision loss or impairment.

The geniculate bodies are part of the auditory pathway in the brainstem. They are two small, rounded eminences located on the lateral side of the upper pons, near the junction with the midbrain. The geniculate bodies are divided into an anterior and a posterior portion, known as the anterior and posterior geniculate bodies, respectively.

The anterior geniculate body receives inputs from the contralateral cochlear nucleus via the trapezoid body, and it is involved in the processing of sound localization. The posterior geniculate body receives inputs from the inferior colliculus via the lateral lemniscus and is involved in the processing of auditory information for conscious perception.

Overall, the geniculate bodies play a critical role in the processing and transmission of auditory information to higher brain areas for further analysis and interpretation.

Tomography is a medical imaging technique used to produce cross-sectional images or slices of specific areas of the body. This technique uses various forms of radiation (X-rays, gamma rays) or sound waves (ultrasound) to create detailed images of the internal structures, such as organs, bones, and tissues. Common types of tomography include Computerized Tomography (CT), Positron Emission Tomography (PET), and Magnetic Resonance Imaging (MRI). The primary advantage of tomography is its ability to provide clear and detailed images of internal structures, allowing healthcare professionals to accurately diagnose and monitor a wide range of medical conditions.

Flicker Fusion is the frequency at which an intermittent light stimulus appears to be completely steady or continuous to the average human observer. In other words, it is the rate at which a flickering light source transitions from being perceived as distinct flashes to a smooth and constant emission of light. The exact threshold can vary depending on factors such as the intensity of the light, its size, and the observer's visual acuity.

Flicker Fusion has important implications in various fields, including visual perception research, display technology, and neurology. In clinical settings, assessing a patient's flicker fusion threshold can help diagnose or monitor conditions affecting the nervous system, such as multiple sclerosis or migraines.

"Macaca mulatta" is the scientific name for the Rhesus macaque, a species of monkey that is native to South, Central, and Southeast Asia. They are often used in biomedical research due to their genetic similarity to humans.

I'm sorry for any confusion, but "reading" is not a term that has a specific medical definition. Reading is the activity or process of deciphering and understanding written words or text. It is a fundamental skill in language acquisition and communication, and is not typically used in a medical context unless there is a concern related to reading difficulties or disorders, such as dyslexia. If you have any questions related to medical terminology or health concerns, I'd be happy to try to help answer those for you!

Medical definitions for visual impairment often vary, but according to the World Health Organization (WHO), visually impaired persons are those who have a best-corrected visual acuity of less than 0.3 (6/12) in their better eye or a visual field of less than 20 degrees in their better eye. This includes people who are blind, as well as those with partial sight.

Visual impairment can range from mild to severe and may result from a variety of causes, including genetic disorders, diseases, trauma, or aging. It is important to note that visual impairment does not necessarily mean total blindness; many visually impaired individuals have some remaining vision and can benefit from low vision services and assistive devices.

Neurological models are simplified representations or simulations of various aspects of the nervous system, including its structure, function, and processes. These models can be theoretical, computational, or physical and are used to understand, explain, and predict neurological phenomena. They may focus on specific neurological diseases, disorders, or functions, such as memory, learning, or movement. The goal of these models is to provide insights into the complex workings of the nervous system that cannot be easily observed or understood through direct examination alone.

In the context of ophthalmology and optometry, glare refers to a visual sensation caused by excessive brightness or contrast that interferes with the ability to see comfortably or clearly. It can be caused by direct or reflected light sources that enter the eye and scatter within the eye or on the surface of the eye, reducing contrast and visibility. Glare can lead to discomfort, disability, or both, and it can significantly impact visual performance in various activities such as driving, reading, and using digital devices. There are different types of glare, including direct glare, reflected glare, and veiling glare, each with its own characteristics and effects on vision.

Papilledema is a medical term that refers to swelling of the optic nerve head, also known as the disc, which is the point where the optic nerve enters the back of the eye (the retina). This swelling can be caused by increased pressure within the skull, such as from brain tumors, meningitis, or idiopathic intracranial hypertension. Papilledema is usually detected through a routine eye examination and may be accompanied by symptoms such as headaches, visual disturbances, and nausea. If left untreated, papilledema can lead to permanent vision loss.

I'm sorry for any confusion, but "Magnetic Fields" is not a term typically used in medical definitions. It is a concept from physics that describes the region around a magnetic material or a moving electric charge where its magnetic influence can be felt.

However, if you're referring to "Magnetic Resonance Imaging (MRI)," it's a common medical imaging technique that uses magnetic fields and radio waves to create detailed images of the organs and tissues within the body. In this context, a strong magnetic field is used to align the spins of certain atoms in the body, and then radio waves are used to knock these atoms out of alignment and measure the energy they release as they realign. This information is used to create detailed images that can help diagnose a variety of medical conditions.

Reproducibility of results in a medical context refers to the ability to obtain consistent and comparable findings when a particular experiment or study is repeated, either by the same researcher or by different researchers, following the same experimental protocol. It is an essential principle in scientific research that helps to ensure the validity and reliability of research findings.

In medical research, reproducibility of results is crucial for establishing the effectiveness and safety of new treatments, interventions, or diagnostic tools. It involves conducting well-designed studies with adequate sample sizes, appropriate statistical analyses, and transparent reporting of methods and findings to allow other researchers to replicate the study and confirm or refute the results.

The lack of reproducibility in medical research has become a significant concern in recent years, as several high-profile studies have failed to produce consistent findings when replicated by other researchers. This has led to increased scrutiny of research practices and a call for greater transparency, rigor, and standardization in the conduct and reporting of medical research.

Refractive errors are a group of vision conditions that include nearsightedness (myopia), farsightedness (hyperopia), astigmatism, and presbyopia. These conditions occur when the shape of the eye prevents light from focusing directly on the retina, causing blurred or distorted vision.

Myopia is a condition where distant objects appear blurry while close-up objects are clear. This occurs when the eye is too long or the cornea is too curved, causing light to focus in front of the retina instead of directly on it.

Hyperopia, on the other hand, is a condition where close-up objects appear blurry while distant objects are clear. This happens when the eye is too short or the cornea is not curved enough, causing light to focus behind the retina.

Astigmatism is a condition that causes blurred vision at all distances due to an irregularly shaped cornea or lens.

Presbyopia is a natural aging process that affects everyone as they get older, usually around the age of 40. It causes difficulty focusing on close-up objects and can be corrected with reading glasses, bifocals, or progressive lenses.

Refractive errors can be diagnosed through a comprehensive eye exam and are typically corrected with eyeglasses, contact lenses, or refractive surgery such as LASIK.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

Sensory deprivation, also known as perceptual isolation or sensory restriction, refers to the deliberate reduction or removal of stimuli from one or more of the senses. This can include limiting input from sight, sound, touch, taste, and smell. The goal is to limit a person's sensory experiences in order to study the effects on cognition, perception, and behavior.

In a clinical context, sensory deprivation can occur as a result of certain medical conditions or treatments, such as blindness, deafness, or pharmacological interventions that affect sensory processing. Prolonged sensory deprivation can lead to significant psychological and physiological effects, including hallucinations, delusions, and decreased cognitive function.

It's important to note that sensory deprivation should not be confused with meditation or relaxation techniques that involve reducing external stimuli in a controlled manner to promote relaxation and focus.

"Cat" is a common name that refers to various species of small carnivorous mammals that belong to the family Felidae. The domestic cat, also known as Felis catus or Felis silvestris catus, is a popular pet and companion animal. It is a subspecies of the wildcat, which is found in Europe, Africa, and Asia.

Domestic cats are often kept as pets because of their companionship, playful behavior, and ability to hunt vermin. They are also valued for their ability to provide emotional support and therapy to people. Cats are obligate carnivores, which means that they require a diet that consists mainly of meat to meet their nutritional needs.

Cats are known for their agility, sharp senses, and predatory instincts. They have retractable claws, which they use for hunting and self-defense. Cats also have a keen sense of smell, hearing, and vision, which allow them to detect prey and navigate their environment.

In medical terms, cats can be hosts to various parasites and diseases that can affect humans and other animals. Some common feline diseases include rabies, feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), and toxoplasmosis. It is important for cat owners to keep their pets healthy and up-to-date on vaccinations and preventative treatments to protect both the cats and their human companions.

Dark adaptation is the process by which the eyes adjust to low levels of light. This process allows the eyes to become more sensitive to light and see better in the dark. It involves the dilation of the pupils, as well as chemical changes in the rods and cones (photoreceptor cells) of the retina. These changes allow the eye to detect even small amounts of light and improve visual acuity in low-light conditions. Dark adaptation typically takes several minutes to occur fully, but can be faster or slower depending on various factors such as age, prior exposure to light, and certain medical conditions. It is an important process for maintaining good vision in a variety of lighting conditions.

Optic neuritis is a medical condition characterized by inflammation and damage to the optic nerve, which transmits visual information from the eye to the brain. This condition can result in various symptoms such as vision loss, pain with eye movement, color vision disturbances, and pupillary abnormalities. Optic neuritis may occur in isolation or be associated with other underlying medical conditions, including multiple sclerosis, neuromyelitis optica, and autoimmune disorders. The diagnosis typically involves a comprehensive eye examination, including visual acuity testing, dilated funduscopic examination, and possibly imaging studies like MRI to evaluate the optic nerve and brain. Treatment options may include corticosteroids or other immunomodulatory therapies to reduce inflammation and prevent further damage to the optic nerve.

Amblyopia is a medical condition that affects the visual system, specifically the way the brain and eyes work together. It is often referred to as "lazy eye" and is characterized by reduced vision in one or both eyes that is not correctable with glasses or contact lenses alone. This occurs because the brain favors one eye over the other, causing the weaker eye to become neglected and underdeveloped.

Amblyopia can result from various conditions such as strabismus (eye misalignment), anisometropia (significant difference in prescription between the two eyes), or deprivation (such as a cataract that blocks light from entering the eye). Treatment for amblyopia typically involves correcting any underlying refractive errors, patching or blurring the stronger eye to force the weaker eye to work, and/or vision therapy. Early intervention is crucial to achieve optimal visual outcomes.

Color vision defects, also known as color blindness, are conditions in which a person has difficulty distinguishing between certain colors. The most common types of color vision defects involve the inability to distinguish between red and green or blue and yellow. These deficiencies result from an alteration or absence of one or more of the three types of cone cells in the retina that are responsible for normal color vision.

In red-green color vision defects, there is a problem with either the red or green cones, or both. This results in difficulty distinguishing between these two colors and their shades. Protanopia is a type of red-green color vision defect where there is an absence of red cone cells, making it difficult to distinguish between red and green as well as between red and black or green and black. Deuteranopia is another type of red-green color vision defect where there is an absence of green cone cells, resulting in similar difficulties distinguishing between red and green, as well as between blue and yellow.

Blue-yellow color vision defects are less common than red-green color vision defects. Tritanopia is a type of blue-yellow color vision defect where there is an absence of blue cone cells, making it difficult to distinguish between blue and yellow, as well as between blue and purple or yellow and pink.

Color vision defects are usually inherited and present from birth, but they can also result from eye diseases, chemical exposure, aging, or medication side effects. They affect both men and women, although red-green color vision defects are more common in men than in women. People with color vision defects may have difficulty with tasks that require color discrimination, such as matching clothes, selecting ripe fruit, reading colored maps, or identifying warning signals. However, most people with mild to moderate color vision defects can adapt and function well in daily life.

The medical definition of 'Automobile Driving' is the act of operating a motor vehicle, typically a car, on public roads or highways. This requires a set of cognitive, physical, and sensory skills to safely control the vehicle, navigate through traffic, and respond to various situations that may arise while driving.

Cognitive skills include attention, memory, decision-making, problem-solving, and judgment. Physical abilities encompass fine motor coordination, reaction time, strength, and flexibility. Sensory functions such as vision, hearing, and touch are also essential for safe driving.

Various medical conditions or medications can impair these skills and affect a person's ability to drive safely. Therefore, it is crucial for individuals to consult with their healthcare providers about any potential risks associated with driving and follow any recommended restrictions or guidelines.

Color vision is the ability to perceive and differentiate colors, which is a result of the way that our eyes and brain process different wavelengths of light. In the eye, there are two types of photoreceptor cells called rods and cones. While rods are more sensitive to low levels of light and help us see in dim conditions, cones are responsible for color vision.

There are three types of cone cells in the human eye, each containing a different type of pigment that is sensitive to specific wavelengths of light. One type of cone cell is most sensitive to short wavelengths (blue light), another is most sensitive to medium wavelengths (green light), and the third is most sensitive to long wavelengths (red light). When light enters the eye, it is absorbed by these pigments in the cones, which then send signals to the brain. The brain interprets these signals and translates them into the perception of color.

People with normal color vision can distinguish between millions of different colors based on the specific combinations of wavelengths that are present in a given scene. However, some people have deficiencies or abnormalities in their color vision, which can make it difficult or impossible to distinguish between certain colors. These conditions are known as color vision deficiencies or color blindness.

A pupil disorder refers to any abnormality or condition affecting the size, shape, or reactivity of the pupils, the circular black openings in the center of the eyes through which light enters. The pupil's primary function is to regulate the amount of light that reaches the retina, adjusting its size accordingly.

There are several types of pupil disorders, including:

1. Anisocoria: A condition characterized by unequal pupil sizes in either one or both eyes. This may be caused by various factors, such as nerve damage, trauma, inflammation, or medication side effects.

2. Horner's syndrome: A neurological disorder affecting the autonomic nervous system, resulting in a smaller pupil (miosis), partial eyelid droop (ptosis), and decreased sweating (anhidrosis) on the same side of the face. It is caused by damage to the sympathetic nerve pathway.

3. Adie's tonic pupil: A condition characterized by a dilated, poorly reactive pupil due to damage to the ciliary ganglion or short ciliary nerves. This disorder usually affects one eye and may be associated with decreased deep tendon reflexes in the affected limbs.

4. Argyll Robertson pupil: A condition where the pupils are small, irregularly shaped, and do not react to light but constrict when focusing on nearby objects (accommodation). This disorder is often associated with neurosyphilis or other brainstem disorders.

5. Pupillary dilation: Abnormally dilated pupils can be a sign of various conditions, such as drug use (e.g., atropine, cocaine), brainstem injury, Adie's tonic pupil, or oculomotor nerve palsy.

6. Pupillary constriction: Abnormally constricted pupils can be a sign of various conditions, such as Horner's syndrome, Argyll Robertson pupil, drug use (e.g., opioids, pilocarpine), or oculomotor nerve palsy.

7. Light-near dissociation: A condition where the pupils do not react to light but constrict when focusing on nearby objects. This can be seen in Argyll Robertson pupil and Adie's tonic pupil.

Prompt evaluation by an ophthalmologist or neurologist is necessary for accurate diagnosis and management of these conditions.

Neurons, also known as nerve cells or neurocytes, are specialized cells that constitute the basic unit of the nervous system. They are responsible for receiving, processing, and transmitting information and signals within the body. Neurons have three main parts: the dendrites, the cell body (soma), and the axon. The dendrites receive signals from other neurons or sensory receptors, while the axon transmits these signals to other neurons, muscles, or glands. The junction between two neurons is called a synapse, where neurotransmitters are released to transmit the signal across the gap (synaptic cleft) to the next neuron. Neurons vary in size, shape, and structure depending on their function and location within the nervous system.

Color perception refers to the ability to detect, recognize, and differentiate various colors and color patterns in the visual field. This complex process involves the functioning of both the eyes and the brain.

The eye's retina contains two types of photoreceptor cells called rods and cones. Rods are more sensitive to light and dark changes and help us see in low-light conditions, but they do not contribute much to color vision. Cones, on the other hand, are responsible for color perception and function best in well-lit conditions.

There are three types of cone cells, each sensitive to a particular range of wavelengths corresponding to blue, green, and red colors. The combination of signals from these three types of cones allows us to perceive a wide spectrum of colors.

The brain then interprets these signals and translates them into the perception of different colors and hues. It is important to note that color perception can be influenced by various factors, including cultural background, personal experiences, and even language. Some individuals may also have deficiencies in color perception due to genetic or acquired conditions, such as color blindness or cataracts.

Sensitivity and specificity are statistical measures used to describe the performance of a diagnostic test or screening tool in identifying true positive and true negative results.

* Sensitivity refers to the proportion of people who have a particular condition (true positives) who are correctly identified by the test. It is also known as the "true positive rate" or "recall." A highly sensitive test will identify most or all of the people with the condition, but may also produce more false positives.
* Specificity refers to the proportion of people who do not have a particular condition (true negatives) who are correctly identified by the test. It is also known as the "true negative rate." A highly specific test will identify most or all of the people without the condition, but may also produce more false negatives.

In medical testing, both sensitivity and specificity are important considerations when evaluating a diagnostic test. High sensitivity is desirable for screening tests that aim to identify as many cases of a condition as possible, while high specificity is desirable for confirmatory tests that aim to rule out the condition in people who do not have it.

It's worth noting that sensitivity and specificity are often influenced by factors such as the prevalence of the condition in the population being tested, the threshold used to define a positive result, and the reliability and validity of the test itself. Therefore, it's important to consider these factors when interpreting the results of a diagnostic test.

Analysis of Variance (ANOVA) is a statistical technique used to compare the means of two or more groups and determine whether there are any significant differences between them. It is a way to analyze the variance in a dataset to determine whether the variability between groups is greater than the variability within groups, which can indicate that the groups are significantly different from one another.

ANOVA is based on the concept of partitioning the total variance in a dataset into two components: variance due to differences between group means (also known as "between-group variance") and variance due to differences within each group (also known as "within-group variance"). By comparing these two sources of variance, ANOVA can help researchers determine whether any observed differences between groups are statistically significant, or whether they could have occurred by chance.

ANOVA is a widely used technique in many areas of research, including biology, psychology, engineering, and business. It is often used to compare the means of two or more experimental groups, such as a treatment group and a control group, to determine whether the treatment had a significant effect. ANOVA can also be used to compare the means of different populations or subgroups within a population, to identify any differences that may exist between them.

Disease progression is the worsening or advancement of a medical condition over time. It refers to the natural course of a disease, including its development, the severity of symptoms and complications, and the impact on the patient's overall health and quality of life. Understanding disease progression is important for developing appropriate treatment plans, monitoring response to therapy, and predicting outcomes.

The rate of disease progression can vary widely depending on the type of medical condition, individual patient factors, and the effectiveness of treatment. Some diseases may progress rapidly over a short period of time, while others may progress more slowly over many years. In some cases, disease progression may be slowed or even halted with appropriate medical interventions, while in other cases, the progression may be inevitable and irreversible.

In clinical practice, healthcare providers closely monitor disease progression through regular assessments, imaging studies, and laboratory tests. This information is used to guide treatment decisions and adjust care plans as needed to optimize patient outcomes and improve quality of life.

The macula lutea, often simply referred to as the macula or fovea centralis, is a part of the eye that is responsible for central vision and color perception. It's located in the center of the retina, the light-sensitive tissue at the back of the eye. The macula contains a high concentration of pigments called xanthophylls, which give it a yellowish color and protect the photoreceptor cells in this area from damage by blue light.

The central part of the macula is called the fovea, which is a small depression that contains only cones, the photoreceptor cells responsible for color vision and high visual acuity. The fovea is surrounded by the parafovea and the perifovea, which contain both cones and rods, the photoreceptor cells responsible for low-light vision and peripheral vision.

Damage to the macula can result in a loss of central vision and color perception, a condition known as age-related macular degeneration (AMD), which is a leading cause of blindness in older adults. Other conditions that can affect the macula include macular edema, macular holes, and macular pucker.

Computer-assisted image processing is a medical term that refers to the use of computer systems and specialized software to improve, analyze, and interpret medical images obtained through various imaging techniques such as X-ray, CT (computed tomography), MRI (magnetic resonance imaging), ultrasound, and others.

The process typically involves several steps, including image acquisition, enhancement, segmentation, restoration, and analysis. Image processing algorithms can be used to enhance the quality of medical images by adjusting contrast, brightness, and sharpness, as well as removing noise and artifacts that may interfere with accurate diagnosis. Segmentation techniques can be used to isolate specific regions or structures of interest within an image, allowing for more detailed analysis.

Computer-assisted image processing has numerous applications in medical imaging, including detection and characterization of lesions, tumors, and other abnormalities; assessment of organ function and morphology; and guidance of interventional procedures such as biopsies and surgeries. By automating and standardizing image analysis tasks, computer-assisted image processing can help to improve diagnostic accuracy, efficiency, and consistency, while reducing the potential for human error.

Depth perception is the ability to accurately judge the distance or separation of an object in three-dimensional space. It is a complex visual process that allows us to perceive the world in three dimensions and to understand the spatial relationships between objects.

Depth perception is achieved through a combination of monocular cues, which are visual cues that can be perceived with one eye, and binocular cues, which require input from both eyes. Monocular cues include perspective (the relative size of objects), texture gradients (finer details become smaller as distance increases), and atmospheric perspective (colors become less saturated and lighter in value as distance increases). Binocular cues include convergence (the degree to which the eyes must turn inward to focus on an object) and retinal disparity (the slight difference in the images projected onto the two retinas due to the slightly different positions of the eyes).

Deficits in depth perception can occur due to a variety of factors, including eye disorders, brain injuries, or developmental delays. These deficits can result in difficulties with tasks such as driving, sports, or navigating complex environments. Treatment for depth perception deficits may include vision therapy, corrective lenses, or surgery.

Ocular adaptation is the ability of the eye to adjust and accommodate to changes in visual input and lighting conditions. This process allows the eye to maintain a clear and focused image over a range of different environments and light levels. There are several types of ocular adaptation, including:

1. Light Adaptation: This refers to the eye's ability to adjust to different levels of illumination. When moving from a dark environment to a bright one, the pupils constrict to let in less light, and the sensitivity of the retina decreases. Conversely, when moving from a bright environment to a dark one, the pupils dilate to let in more light, and the sensitivity of the retina increases.
2. Dark Adaptation: This is the process by which the eye adjusts to low light conditions. It involves the dilation of the pupils and an increase in the sensitivity of the rods (specialised cells in the retina that are responsible for vision in low light conditions). Dark adaptation can take several minutes to occur fully.
3. Color Adaptation: This refers to the eye's ability to adjust to changes in the color temperature of light sources. For example, when moving from a room lit by incandescent light to one lit by fluorescent light, the eye may need to adjust its perception of colors to maintain accurate color vision.
4. Accommodation: This is the process by which the eye changes focus from distant to near objects. The lens of the eye changes shape to bend the light rays entering the eye and bring them into sharp focus on the retina.

Overall, ocular adaptation is an essential function that allows us to see clearly and accurately in a wide range of environments and lighting conditions.

Strabismus is a condition of the ocular muscles where the eyes are not aligned properly and point in different directions. One eye may turn inward, outward, upward, or downward while the other one remains fixed and aligns normally. This misalignment can occur occasionally or constantly. Strabismus is also commonly referred to as crossed eyes or walleye. The condition can lead to visual impairments such as amblyopia (lazy eye) and depth perception problems if not treated promptly and effectively, usually through surgery, glasses, or vision therapy.

"Field Dependence-Independence" is not a term used in medical definitions. However, it is a concept in the field of psychology, particularly in the area of perception and cognition.

Field dependence-independence is a personality trait that refers to an individual's ability to perceive and process information independently from the surrounding environment or "field." It is a measure of how much an individual's cognitive style is influenced by contextual cues and stimuli in their environment.

Individuals who are field-dependent tend to be heavily influenced by their surroundings and have difficulty separating relevant from irrelevant information. They may have trouble focusing on specific details when there are distractions or competing stimuli in the environment. In contrast, individuals who are field-independent are less influenced by their surroundings and can focus more easily on specific details and tasks, even in the presence of distractions.

Field dependence-independence is often assessed using psychometric tests such as the Embedded Figures Test (EFT) or the Rod and Frame Test (RFT). These tests measure an individual's ability to perceive and process information independently from their environment, providing insights into their cognitive style and problem-solving abilities.

Cerebral dominance is a concept in neuropsychology that refers to the specialization of one hemisphere of the brain over the other for certain cognitive functions. In most people, the left hemisphere is dominant for language functions such as speaking and understanding spoken or written language, while the right hemisphere is dominant for non-verbal functions such as spatial ability, face recognition, and artistic ability.

Cerebral dominance does not mean that the non-dominant hemisphere is incapable of performing the functions of the dominant hemisphere, but rather that it is less efficient or specialized in those areas. The concept of cerebral dominance has been used to explain individual differences in cognitive abilities and learning styles, as well as the laterality of brain damage and its effects on cognition and behavior.

It's important to note that cerebral dominance is a complex phenomenon that can vary between individuals and can be influenced by various factors such as genetics, environment, and experience. Additionally, recent research has challenged the strict lateralization of functions and suggested that there is more functional overlap and interaction between the two hemispheres than previously thought.

Angle-closure glaucoma is a type of glaucoma that is characterized by the sudden or gradually increasing pressure in the eye (intraocular pressure) due to the closure or narrowing of the angle between the iris and cornea. This angle is where the drainage system of the eye, called the trabecular meshwork, is located. When the angle becomes too narrow or closes completely, fluid cannot properly drain from the eye, leading to a buildup of pressure that can damage the optic nerve and cause permanent vision loss.

Angle-closure glaucoma can be either acute or chronic. Acute angle-closure glaucoma is a medical emergency that requires immediate treatment to prevent permanent vision loss. It is characterized by sudden symptoms such as severe eye pain, nausea and vomiting, blurred vision, halos around lights, and redness of the eye.

Chronic angle-closure glaucoma, on the other hand, develops more slowly over time and may not have any noticeable symptoms until significant damage has already occurred. It is important to diagnose and treat angle-closure glaucoma as early as possible to prevent vision loss. Treatment options include medications to lower eye pressure, laser treatment to create a new opening for fluid drainage, or surgery to improve the flow of fluid out of the eye.

I'm sorry for any confusion, but "Macaca" is not a medical term. It is the name of a genus that includes several species of monkeys, commonly known as macaques. These primates are often used in biomedical research due to their similarities with humans in terms of genetics and physiology. If you have any questions related to medicine or health, I would be happy to try to help answer them.

Optic atrophy is a medical term that refers to the degeneration and shrinkage (atrophy) of the optic nerve, which transmits visual information from the eye to the brain. This condition can result in various vision abnormalities, including loss of visual acuity, color vision deficiencies, and peripheral vision loss.

Optic atrophy can occur due to a variety of causes, such as:

* Traumatic injuries to the eye or optic nerve
* Glaucoma
* Optic neuritis (inflammation of the optic nerve)
* Ischemic optic neuropathy (reduced blood flow to the optic nerve)
* Compression or swelling of the optic nerve
* Hereditary or congenital conditions affecting the optic nerve
* Toxins and certain medications that can damage the optic nerve.

The diagnosis of optic atrophy typically involves a comprehensive eye examination, including visual acuity testing, refraction assessment, slit-lamp examination, and dilated funduscopic examination to evaluate the health of the optic nerve. In some cases, additional diagnostic tests such as visual field testing, optical coherence tomography (OCT), or magnetic resonance imaging (MRI) may be necessary to confirm the diagnosis and determine the underlying cause.

There is no specific treatment for optic atrophy, but addressing the underlying cause can help prevent further damage to the optic nerve. In some cases, vision rehabilitation may be recommended to help patients adapt to their visual impairment.

A trabeculectomy is a surgical procedure performed on the eye to treat glaucoma, an eye condition characterized by increased pressure within the eye that can lead to optic nerve damage and vision loss. The main goal of this operation is to create a new channel for the aqueous humor (the clear fluid inside the eye) to drain out, thus reducing the intraocular pressure (IOP).

During the trabeculectomy procedure, a small flap is made in the sclera (the white part of the eye), and a piece of the trabecular meshwork (a structure inside the eye that helps regulate the flow of aqueous humor) is removed. This opening allows the aqueous humor to bypass the obstructed drainage system and form a bleb, a small blister-like sac on the surface of the eye, which absorbs the fluid and reduces IOP.

The success of trabeculectomy depends on various factors, including the patient's age, type and severity of glaucoma, previous treatments, and overall health. Potential complications may include infection, bleeding, cataract formation, hypotony (abnormally low IOP), or failure to control IOP. Regular follow-up appointments with an ophthalmologist are necessary to monitor the eye's response to the surgery and manage any potential issues that may arise.

Optical illusions are visual phenomena that occur when the brain perceives an image or scene differently from the actual physical properties of that image or scene. They often result from the brain's attempt to interpret and make sense of ambiguous, contradictory, or incomplete information provided by the eyes. This can lead to visually perceived images that are different from the objective reality. Optical illusions can be categorized into different types such as literal illusions, physiological illusions, and cognitive illusions, based on the nature of the illusion and the underlying cause.

Size perception in a medical context typically refers to the way an individual's brain interprets and perceives the size or volume of various stimuli. This can include visual stimuli, such as objects or distances, as well as tactile stimuli, like the size of an object being held or touched.

Disorders in size perception can occur due to neurological conditions, brain injuries, or certain developmental disorders. For example, individuals with visual agnosia may have difficulty recognizing or perceiving the size of objects they see, even though their eyes are functioning normally. Similarly, those with somatoparaphrenia may not recognize the size of their own limbs due to damage in specific areas of the brain.

It's important to note that while 'size perception' is not a medical term per se, it can still be used in a medical or clinical context to describe these types of symptoms and conditions.

Eye diseases are a range of conditions that affect the eye or visual system, causing damage to vision and, in some cases, leading to blindness. These diseases can be categorized into various types, including:

1. Refractive errors: These include myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia, which affect the way light is focused on the retina and can usually be corrected with glasses or contact lenses.
2. Cataracts: A clouding of the lens inside the eye that leads to blurry vision, glare, and decreased contrast sensitivity. Cataract surgery is the most common treatment for this condition.
3. Glaucoma: A group of diseases characterized by increased pressure in the eye, leading to damage to the optic nerve and potential blindness if left untreated. Treatment includes medications, laser therapy, or surgery.
4. Age-related macular degeneration (AMD): A progressive condition that affects the central part of the retina called the macula, causing blurry vision and, in advanced stages, loss of central vision. Treatment may include anti-VEGF injections, laser therapy, or nutritional supplements.
5. Diabetic retinopathy: A complication of diabetes that affects the blood vessels in the retina, leading to bleeding, leakage, and potential blindness if left untreated. Treatment includes laser therapy, anti-VEGF injections, or surgery.
6. Retinal detachment: A separation of the retina from its underlying tissue, which can lead to vision loss if not treated promptly with surgery.
7. Amblyopia (lazy eye): A condition where one eye does not develop normal vision, often due to a misalignment or refractive error in childhood. Treatment includes correcting the underlying problem and encouraging the use of the weaker eye through patching or other methods.
8. Strabismus (crossed eyes): A misalignment of the eyes that can lead to amblyopia if not treated promptly with surgery, glasses, or other methods.
9. Corneal diseases: Conditions that affect the transparent outer layer of the eye, such as keratoconus, Fuchs' dystrophy, and infectious keratitis, which can lead to vision loss if not treated promptly.
10. Uveitis: Inflammation of the middle layer of the eye, which can cause vision loss if not treated promptly with anti-inflammatory medications or surgery.

Follow-up studies are a type of longitudinal research that involve repeated observations or measurements of the same variables over a period of time, in order to understand their long-term effects or outcomes. In medical context, follow-up studies are often used to evaluate the safety and efficacy of medical treatments, interventions, or procedures.

In a typical follow-up study, a group of individuals (called a cohort) who have received a particular treatment or intervention are identified and then followed over time through periodic assessments or data collection. The data collected may include information on clinical outcomes, adverse events, changes in symptoms or functional status, and other relevant measures.

The results of follow-up studies can provide important insights into the long-term benefits and risks of medical interventions, as well as help to identify factors that may influence treatment effectiveness or patient outcomes. However, it is important to note that follow-up studies can be subject to various biases and limitations, such as loss to follow-up, recall bias, and changes in clinical practice over time, which must be carefully considered when interpreting the results.

Phosphenes are described as the phenomenon of seeing light without light actually entering the eye. This can occur through various mechanisms such as applying pressure to the eyeball, due to rubbing or closing the eyes tightly, or after exposure to bright lights. Additionally, phosphenes can also be experienced during conditions like migraines or as a result of certain neurological disorders.

In simpler terms, phosphenes are the sensation of seeing flashes of light caused by internal stimuli rather than external light input.

Retinal cone photoreceptor cells are specialized neurons located in the retina of the eye, responsible for visual phototransduction and color vision. They are one of the two types of photoreceptors, with the other being rods, which are more sensitive to low light levels. Cones are primarily responsible for high-acuity, color vision during daylight or bright-light conditions.

There are three types of cone cells, each containing different photopigments that absorb light at distinct wavelengths: short (S), medium (M), and long (L) wavelengths, which correspond to blue, green, and red light, respectively. The combination of signals from these three types of cones allows the human visual system to perceive a wide range of colors and discriminate between them. Cones are densely packed in the central region of the retina, known as the fovea, which provides the highest visual acuity.

Distance perception refers to the ability to accurately judge the distance or depth of an object in relation to oneself or other objects. It is a complex process that involves both visual and non-visual cues, such as perspective, size, texture, motion parallax, binocular disparity, and familiarity with the object or scene.

In the visual system, distance perception is primarily mediated by the convergence of the two eyes on an object, which provides information about its depth and location in three-dimensional space. The brain then integrates this information with other sensory inputs and prior knowledge to create a coherent perception of the environment.

Disorders of distance perception can result from various conditions that affect the visual system, such as amblyopia, strabismus, or traumatic brain injury. These disorders can cause difficulties in tasks that require accurate depth perception, such as driving, sports, or manual work.

The eye is the organ of sight, primarily responsible for detecting and focusing on visual stimuli. It is a complex structure composed of various parts that work together to enable vision. Here are some of the main components of the eye:

1. Cornea: The clear front part of the eye that refracts light entering the eye and protects the eye from harmful particles and microorganisms.
2. Iris: The colored part of the eye that controls the amount of light reaching the retina by adjusting the size of the pupil.
3. Pupil: The opening in the center of the iris that allows light to enter the eye.
4. Lens: A biconvex structure located behind the iris that further refracts light and focuses it onto the retina.
5. Retina: A layer of light-sensitive cells (rods and cones) at the back of the eye that convert light into electrical signals, which are then transmitted to the brain via the optic nerve.
6. Optic Nerve: The nerve that carries visual information from the retina to the brain.
7. Vitreous: A clear, gel-like substance that fills the space between the lens and the retina, providing structural support to the eye.
8. Conjunctiva: A thin, transparent membrane that covers the front of the eye and the inner surface of the eyelids.
9. Extraocular Muscles: Six muscles that control the movement of the eye, allowing for proper alignment and focus.

The eye is a remarkable organ that allows us to perceive and interact with our surroundings. Various medical specialties, such as ophthalmology and optometry, are dedicated to the diagnosis, treatment, and management of various eye conditions and diseases.

Pseudotumor cerebri, also known as idiopathic intracranial hypertension, is a condition characterized by increased pressure around the brain without any identifiable cause such as a tumor or other space-occupying lesion. The symptoms mimic those of a brain mass, hence the term "pseudotumor."

The primary manifestation of this condition is headaches, often accompanied by vision changes like blurry vision, double vision, or temporary loss of vision, and pulsatile tinnitus (a rhythmic whooshing sound in the ears). Other symptoms can include neck pain, nausea, vomiting, and papilledema (swelling of the optic nerve disc). If left untreated, pseudotumor cerebri can lead to permanent vision loss.

The exact cause of pseudotumor cerebri remains unknown, but it has been associated with certain factors such as obesity, rapid weight gain, female gender (particularly during reproductive years), sleep apnea, and the use of certain medications like tetracyclines, vitamin A derivatives, and steroid withdrawal. Diagnosis typically involves a series of tests including neurological examination, imaging studies (such as MRI or CT scan), and lumbar puncture to measure cerebrospinal fluid pressure. Treatment usually focuses on lowering intracranial pressure through medications, weight loss, and sometimes surgical interventions like optic nerve sheath fenestration or shunting procedures.

Vision screening is a quick and cost-effective method used to identify individuals who are at risk of vision problems or eye diseases. It is not a comprehensive eye examination, but rather an initial evaluation that helps to determine if a further, more in-depth examination by an eye care professional is needed. Vision screenings typically involve tests for visual acuity, distance and near vision, color perception, depth perception, and alignment of the eyes. The goal of vision screening is to detect potential vision issues early on, so that they can be treated promptly and effectively, thereby preventing or minimizing any negative impact on a person's overall vision and quality of life.

I'm sorry for any confusion, but "lighting" does not have a specific medical definition. In a general context, lighting refers to the arrangement or use of light sources to achieve a particular effect or atmosphere. However, if you are referring to a term in medicine that may be similar to "lighting," you might be thinking of "lumination" or "illumination," which refer to the act of providing or admitting light, especially for medical examination or surgical procedures. I hope this helps! If you have any other questions, please don't hesitate to ask.

Prospective studies, also known as longitudinal studies, are a type of cohort study in which data is collected forward in time, following a group of individuals who share a common characteristic or exposure over a period of time. The researchers clearly define the study population and exposure of interest at the beginning of the study and follow up with the participants to determine the outcomes that develop over time. This type of study design allows for the investigation of causal relationships between exposures and outcomes, as well as the identification of risk factors and the estimation of disease incidence rates. Prospective studies are particularly useful in epidemiology and medical research when studying diseases with long latency periods or rare outcomes.

Macular degeneration, also known as age-related macular degeneration (AMD), is a medical condition that affects the central part of the retina, called the macula. The macula is responsible for sharp, detailed vision, which is necessary for activities such as reading, driving, and recognizing faces.

In AMD, there is a breakdown or deterioration of the macula, leading to gradual loss of central vision. There are two main types of AMD: dry (atrophic) and wet (exudative). Dry AMD is more common and progresses more slowly, while wet AMD is less common but can cause rapid and severe vision loss if left untreated.

The exact causes of AMD are not fully understood, but risk factors include age, smoking, family history, high blood pressure, obesity, and exposure to sunlight. While there is no cure for AMD, treatments such as vitamin supplements, laser therapy, and medication injections can help slow its progression and reduce the risk of vision loss.

In the context of medical terminology, 'color' is not defined specifically with a unique meaning. Instead, it generally refers to the characteristic or appearance of something, particularly in relation to the color that a person may observe visually. For instance, doctors may describe the color of a patient's skin, eyes, hair, or bodily fluids to help diagnose medical conditions or monitor their progression.

For example, jaundice is a yellowing of the skin and whites of the eyes that can indicate liver problems, while cyanosis refers to a bluish discoloration of the skin and mucous membranes due to insufficient oxygen in the blood. Similarly, doctors may describe the color of stool or urine to help diagnose digestive or kidney issues.

Therefore, 'color' is not a medical term with a specific definition but rather a general term used to describe various visual characteristics of the body and bodily fluids that can provide important diagnostic clues for healthcare professionals.

Pituitary neoplasms refer to abnormal growths or tumors in the pituitary gland, a small endocrine gland located at the base of the brain. These neoplasms can be benign (non-cancerous) or malignant (cancerous), with most being benign. They can vary in size and may cause various symptoms depending on their location, size, and hormonal activity.

Pituitary neoplasms can produce and secrete excess hormones, leading to a variety of endocrine disorders such as Cushing's disease (caused by excessive ACTH production), acromegaly (caused by excessive GH production), or prolactinoma (caused by excessive PRL production). They can also cause local compression symptoms due to their size, leading to headaches, vision problems, and cranial nerve palsies.

The exact causes of pituitary neoplasms are not fully understood, but genetic factors, radiation exposure, and certain inherited conditions may increase the risk of developing these tumors. Treatment options for pituitary neoplasms include surgical removal, radiation therapy, and medical management with drugs that can help control hormonal imbalances.

An illusion is a perception in the brain that does not match the actual stimulus in the environment. It is often described as a false or misinterpreted sensory experience, where the senses perceive something that is different from the reality. Illusions can occur in any of the senses, including vision, hearing, touch, taste, and smell.

In medical terms, illusions are sometimes associated with certain neurological conditions, such as migraines, brain injuries, or mental health disorders like schizophrenia. They can also be a side effect of certain medications or substances. In these cases, the illusions may be a symptom of an underlying medical condition and should be evaluated by a healthcare professional.

It's important to note that while illusions are often used in the context of entertainment and art, they can also have serious implications for individuals who experience them frequently or as part of a medical condition.

Night vision refers to the ability to see in low light conditions, typically during night time. In a medical context, it often relates to the functionality of the eye and visual system. There are two types of night vision:

1. Scotopic vision: This is the primary type of night vision, enabled by the rod cells in our retina which are highly sensitive to light but lack color vision. During twilight or night conditions, when light levels are low, the rods take over from the cone cells (which are responsible for color and daytime vision) and provide us with limited vision, typically in shades of gray.

2. Mesopic vision: This is a state between photopic (daytime) and scotopic (night-time) vision, where both rod and cone cells contribute to vision. It allows for better color discrimination and visual acuity compared to scotopic vision alone.

In some cases, night vision can be impaired due to eye conditions such as cataracts, glaucoma, or retinal disorders. There are also medical devices called night vision goggles that amplify available light to enhance a person's ability to see in low-light environments.

A pupillary reflex is a type of reflex that involves the constriction or dilation of the pupils in response to changes in light or near vision. It is mediated by the optic and oculomotor nerves. The pupillary reflex helps regulate the amount of light that enters the eye, improving visual acuity and protecting the retina from excessive light exposure.

In a clinical setting, the pupillary reflex is often assessed as part of a neurological examination. A normal pupillary reflex consists of both direct and consensual responses. The direct response occurs when light is shone into one eye and the pupil of that same eye constricts. The consensual response occurs when light is shone into one eye, causing the pupil of the other eye to also constrict.

Abnormalities in the pupillary reflex can indicate various neurological conditions, such as brainstem injuries or diseases affecting the optic or oculomotor nerves.

Perceptual distortion is not explicitly defined within the realm of medicine, but it does fall under the broader category of cognitive impairments and abnormalities. It generally refers to the incorrect interpretation or misrepresentation of sensory information by the brain. This can result in various experiences such as hallucinations, illusions, or distorted perceptions of reality. Perceptual distortions are often associated with certain medical conditions like mental disorders (e.g., schizophrenia, bipolar disorder), neurological disorders (e.g., migraines, epilepsy), and substance use disorders.

Color perception tests are a type of examination used to evaluate an individual's ability to perceive and distinguish different colors. These tests typically consist of a series of plates or images that contain various patterns or shapes displayed in different colors. The person being tested is then asked to identify or match the colors based on specific instructions.

There are several types of color perception tests, including:

1. Ishihara Test: This is a commonly used test for red-green color deficiency. It consists of a series of plates with circles made up of dots in different sizes and colors. Within these circles, there may be a number or symbol visible only to those with normal color vision or to those with specific types of color blindness.
2. Farnsworth D-15 Test: This test measures an individual's ability to arrange colored caps in a specific order based on their hue. It is often used to diagnose and monitor the progression of color vision deficiencies.
3. Hardy-Rand-Rittler (HRR) Test: This is another type of color arrangement test that measures an individual's ability to distinguish between different colors based on their hue, saturation, and brightness.
4. Color Discrimination Tests: These tests measure an individual's ability to distinguish between two similar colors that are presented side by side or in close proximity.
5. Anomaloscope Test: This is a more sophisticated test that measures the degree of color vision deficiency by asking the person to match the brightness and hue of two lights.

Color perception tests are often used in occupational settings, such as aviation, military, and manufacturing, where color discrimination is critical for safety and performance. They may also be used in educational and clinical settings to diagnose and monitor color vision deficiencies.

Ocular dominance refers to the preference of one eye over the other in terms of visual perception and processing. In other words, it is the tendency for an individual to rely more heavily on the input from one particular eye when interpreting visual information. This can have implications in various visual tasks such as depth perception, aiming, and targeting.

Ocular dominance can be determined through a variety of tests, including the Miles test, the Porta test, or simply by observing which eye a person uses to align a visual target. It is important to note that ocular dominance does not necessarily indicate any sort of visual impairment or deficit; rather, it is a normal variation in the way that visual information is processed by the brain.

In the context of medical terminology, "light" doesn't have a specific or standardized definition on its own. However, it can be used in various medical terms and phrases. For example, it could refer to:

1. Visible light: The range of electromagnetic radiation that can be detected by the human eye, typically between wavelengths of 400-700 nanometers. This is relevant in fields such as ophthalmology and optometry.
2. Therapeutic use of light: In some therapies, light is used to treat certain conditions. An example is phototherapy, which uses various wavelengths of ultraviolet (UV) or visible light for conditions like newborn jaundice, skin disorders, or seasonal affective disorder.
3. Light anesthesia: A state of reduced consciousness in which the patient remains responsive to verbal commands and physical stimulation. This is different from general anesthesia where the patient is completely unconscious.
4. Pain relief using light: Certain devices like transcutaneous electrical nerve stimulation (TENS) units have a 'light' setting, indicating lower intensity or frequency of electrical impulses used for pain management.

Without more context, it's hard to provide a precise medical definition of 'light'.

A laser is not a medical term per se, but a physical concept that has important applications in medicine. The term "LASER" stands for "Light Amplification by Stimulated Emission of Radiation." It refers to a device that produces and amplifies light with specific characteristics, such as monochromaticity (single wavelength), coherence (all waves moving in the same direction), and high intensity.

In medicine, lasers are used for various therapeutic and diagnostic purposes, including surgery, dermatology, ophthalmology, and dentistry. They can be used to cut, coagulate, or vaporize tissues with great precision, minimizing damage to surrounding structures. Additionally, lasers can be used to detect and measure physiological parameters, such as blood flow and oxygen saturation.

It's important to note that while lasers are powerful tools in medicine, they must be used by trained professionals to ensure safe and effective treatment.

The temporal lobe is one of the four main lobes of the cerebral cortex in the brain, located on each side of the head roughly level with the ears. It plays a major role in auditory processing, memory, and emotion. The temporal lobe contains several key structures including the primary auditory cortex, which is responsible for analyzing sounds, and the hippocampus, which is crucial for forming new memories. Damage to the temporal lobe can result in various neurological symptoms such as hearing loss, memory impairment, and changes in emotional behavior.

Ophthalmology is a branch of medicine that deals with the diagnosis, treatment, and prevention of diseases and disorders of the eye and visual system. It is a surgical specialty, and ophthalmologists are medical doctors who complete additional years of training to become experts in eye care. They are qualified to perform eye exams, diagnose and treat eye diseases, prescribe glasses and contact lenses, and perform eye surgery. Some subspecialties within ophthalmology include cornea and external disease, glaucoma, neuro-ophthalmology, pediatric ophthalmology, retina and vitreous, and oculoplastics.

Ocular albinism is a type of albinism that primarily affects the eyes. It is a genetic disorder characterized by the reduction or absence of melanin, the pigment responsible for coloring the skin, hair, and eyes. In ocular albinism, melanin production is deficient in the eyes, leading to various eye abnormalities.

The main features of ocular albinism include:

1. Nystagmus: Rapid, involuntary back-and-forth movement of the eyes.
2. Iris transillumination: The iris appears translucent due to the lack of pigment, allowing light to pass through easily. This can be observed using a light source shone into the eye.
3. Foveal hypoplasia: Underdevelopment or absence of the fovea, a small pit in the retina responsible for sharp, central vision.
4. Photophobia: Increased sensitivity to light due to the lack of pigment in the eyes.
5. Strabismus: Misalignment of the eyes, which can result in double vision or lazy eye.
6. Reduced visual acuity: Decreased ability to see clearly, even with corrective lenses.

Ocular albinism is typically inherited as an X-linked recessive trait, meaning it primarily affects males, while females can be carriers of the condition. However, there are also autosomal recessive forms of ocular albinism that can affect both males and females equally. Treatment for ocular albinism usually involves managing symptoms with corrective lenses, low-vision aids, and vision therapy to improve visual skills.

Myopia, also known as nearsightedness, is a common refractive error of the eye. It occurs when the eye is either too long or the cornea (the clear front part of the eye) is too curved. As a result, light rays focus in front of the retina instead of directly on it, causing distant objects to appear blurry while close objects remain clear.

Myopia typically develops during childhood and can progress gradually or rapidly until early adulthood. It can be corrected with glasses, contact lenses, or refractive surgery such as LASIK. Regular eye examinations are essential for people with myopia to monitor any changes in their prescription and ensure proper correction.

While myopia is generally not a serious condition, high levels of nearsightedness can increase the risk of certain eye diseases, including cataracts, glaucoma, retinal detachment, and myopic degeneration. Therefore, it's crucial to manage myopia effectively and maintain regular follow-ups with an eye care professional.

"Galago" is not a term used in human or animal medicine. It is the scientific name for a group of small, nocturnal primates native to continental Africa, also known as bushbabies or nagapies. They are not typically associated with medical conditions or treatments. If you have any questions about primatology or zoology, I would be happy to try and help answer those!

The Automobile Driver Examination is a medical definition that refers to the process of evaluating an individual's physical and mental fitness to operate a motor vehicle. The examination typically includes a series of tests designed to assess the person's vision, hearing, reaction time, cognitive abilities, and overall health status.

The purpose of the examination is to ensure that drivers are capable of operating their vehicles safely and reducing the risk of accidents on the road. In many jurisdictions, driver examinations are required for individuals seeking to obtain a new driver's license or renew an existing one, particularly for those in certain age groups or with medical conditions that may affect their ability to drive.

The examination is usually conducted by a licensed healthcare professional, such as a doctor or nurse practitioner, who has been trained to assess the driver's fitness to operate a motor vehicle. The results of the examination are then used to determine whether the individual is medically fit to drive and what, if any, restrictions or accommodations may be necessary to ensure their safety and the safety of others on the road.

An algorithm is not a medical term, but rather a concept from computer science and mathematics. In the context of medicine, algorithms are often used to describe step-by-step procedures for diagnosing or managing medical conditions. These procedures typically involve a series of rules or decision points that help healthcare professionals make informed decisions about patient care.

For example, an algorithm for diagnosing a particular type of heart disease might involve taking a patient's medical history, performing a physical exam, ordering certain diagnostic tests, and interpreting the results in a specific way. By following this algorithm, healthcare professionals can ensure that they are using a consistent and evidence-based approach to making a diagnosis.

Algorithms can also be used to guide treatment decisions. For instance, an algorithm for managing diabetes might involve setting target blood sugar levels, recommending certain medications or lifestyle changes based on the patient's individual needs, and monitoring the patient's response to treatment over time.

Overall, algorithms are valuable tools in medicine because they help standardize clinical decision-making and ensure that patients receive high-quality care based on the latest scientific evidence.

Ocular refraction is a medical term that refers to the bending of light as it passes through the optical media of the eye, including the cornea and lens. This process allows the eye to focus light onto the retina, creating a clear image. The refractive power of the eye is determined by the curvature and transparency of these structures.

In a normal eye, light rays are bent or refracted in such a way that they converge at a single point on the retina, producing a sharp and focused image. However, if the curvature of the cornea or lens is too steep or too flat, the light rays may not converge properly, resulting in a refractive error such as myopia (nearsightedness), hyperopia (farsightedness), or astigmatism.

Ocular refraction can be measured using a variety of techniques, including retinoscopy, automated refraction, and subjective refraction. These measurements are used to determine the appropriate prescription for corrective lenses such as eyeglasses or contact lenses. In some cases, ocular refractive errors may be corrected surgically through procedures such as LASIK or PRK.

Perceptual masking, also known as sensory masking or just masking, is a concept in sensory perception that refers to the interference in the ability to detect or recognize a stimulus (the target) due to the presence of another stimulus (the mask). This phenomenon can occur across different senses, including audition and vision.

In the context of hearing, perceptual masking occurs when one sound (the masker) makes it difficult to hear another sound (the target) because the two sounds are presented simultaneously or in close proximity to each other. The masker can make the target sound less detectable, harder to identify, or even completely inaudible.

There are different types of perceptual masking, including:

1. Simultaneous Masking: When the masker and target sounds occur at the same time.
2. Temporal Masking: When the masker sound precedes or follows the target sound by a short period. This type of masking can be further divided into forward masking (when the masker comes before the target) and backward masking (when the masker comes after the target).
3. Informational Masking: A more complex form of masking that occurs when the listener's cognitive processes, such as attention or memory, are affected by the presence of the masker sound. This type of masking can make it difficult to understand speech in noisy environments, even if the signal-to-noise ratio is favorable.

Perceptual masking has important implications for understanding and addressing hearing difficulties, particularly in situations with background noise or multiple sounds occurring simultaneously.

Optic disk drusen are small, calcified deposits that form within the optic nerve head, also known as the optic disc. They are made up of protein and calcium salts and can vary in size and number. These deposits can be seen on ophthalmic examination using an instrument called an ophthalmoscope.

Optic disk drusen are typically asymptomatic and are often discovered during routine eye examinations. However, in some cases, they may cause visual disturbances or even vision loss if they compress the optic nerve fibers. They can also increase the risk of developing other eye conditions such as glaucoma.

Optic disk drusen are more commonly found in individuals with a family history of the condition and tend to occur in younger people, typically before the age of 40. While there is no cure for optic disk drusen, regular eye examinations can help monitor any changes in the condition and manage any associated visual symptoms or complications.

Gonioscopy is a diagnostic procedure in ophthalmology used to examine the anterior chamber angle, which is the area where the iris and cornea meet. This examination helps to evaluate the drainage pathways of the eye for conditions such as glaucoma. A special contact lens called a goniolens is placed on the cornea during the procedure to allow the healthcare provider to visualize the angle using a biomicroscope. The lens may be coupled with a mirrored or prismatic surface to enhance the view of the angle. Gonioscopy can help detect conditions like narrow angles, closed angles, neovascularization, and other abnormalities that might contribute to glaucoma development or progression.

Ophthalmologic surgical procedures refer to various types of surgeries performed on the eye and its surrounding structures by trained medical professionals called ophthalmologists. These procedures aim to correct or improve vision, diagnose and treat eye diseases or injuries, and enhance the overall health and functionality of the eye. Some common examples of ophthalmologic surgical procedures include:

1. Cataract Surgery: This procedure involves removing a cloudy lens (cataract) from the eye and replacing it with an artificial intraocular lens (IOL).
2. LASIK (Laser-Assisted In Situ Keratomileusis): A type of refractive surgery that uses a laser to reshape the cornea, correcting nearsightedness, farsightedness, and astigmatism.
3. Glaucoma Surgery: Several surgical options are available for treating glaucoma, including laser trabeculoplasty, traditional trabeculectomy, and various drainage device implantations. These procedures aim to reduce intraocular pressure (IOP) and prevent further optic nerve damage.
4. Corneal Transplant: This procedure involves replacing a damaged or diseased cornea with a healthy donor cornea to restore vision and improve the eye's appearance.
5. Vitreoretinal Surgery: These procedures focus on treating issues within the vitreous humor (gel-like substance filling the eye) and the retina, such as retinal detachment, macular holes, or diabetic retinopathy.
6. Strabismus Surgery: This procedure aims to correct misalignment of the eyes (strabismus) by adjusting the muscles responsible for eye movement.
7. Oculoplastic Surgery: These procedures involve reconstructive, cosmetic, and functional surgeries around the eye, such as eyelid repair, removal of tumors, or orbital fracture repairs.
8. Pediatric Ophthalmologic Procedures: Various surgical interventions are performed on children to treat conditions like congenital cataracts, amblyopia (lazy eye), or blocked tear ducts.

These are just a few examples of ophthalmic surgical procedures. The specific treatment plan will depend on the individual's condition and overall health.

Electrooculography (EOG) is a technique for measuring the resting potential of the eye and the changes in this potential that occur with eye movements. It involves placing electrodes near the eyes to detect the small electric fields generated by the movement of the eyeball within the surrounding socket. This technique is used in research and clinical settings to study eye movements and their control, as well as in certain diagnostic applications such as assessing the function of the oculomotor system in patients with neurological disorders.

Optometry is a healthcare profession that involves examining, diagnosing, and treating disorders related to vision. Optometrists are the primary healthcare practitioners who specialize in prescribing and fitting eyeglasses and contact lenses to correct refractive errors such as myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia. They also diagnose and manage various eye diseases, including glaucoma, cataracts, and age-related macular degeneration. Optometrists may provide low vision care services to individuals with visual impairments and can offer pre- and post-operative care for patients undergoing eye surgery.

Optometry is a regulated profession that requires extensive education and training, including the completion of a Doctor of Optometry (O.D.) degree program and passing national and state licensing exams. In some jurisdictions, optometrists may also prescribe certain medications to treat eye conditions and diseases.

Physiological adaptation refers to the changes or modifications that occur in an organism's biological functions or structures as a result of environmental pressures or changes. These adaptations enable the organism to survive and reproduce more successfully in its environment. They can be short-term, such as the constriction of blood vessels in response to cold temperatures, or long-term, such as the evolution of longer limbs in animals that live in open environments.

In the context of human physiology, examples of physiological adaptation include:

1. Acclimatization: The process by which the body adjusts to changes in environmental conditions, such as altitude or temperature. For example, when a person moves to a high-altitude location, their body may produce more red blood cells to compensate for the lower oxygen levels, leading to improved oxygen delivery to tissues.

2. Exercise adaptation: Regular physical activity can lead to various physiological adaptations, such as increased muscle strength and endurance, enhanced cardiovascular function, and improved insulin sensitivity.

3. Hormonal adaptation: The body can adjust hormone levels in response to changes in the environment or internal conditions. For instance, during prolonged fasting, the body releases stress hormones like cortisol and adrenaline to help maintain energy levels and prevent muscle wasting.

4. Sensory adaptation: Our senses can adapt to different stimuli over time. For example, when we enter a dark room after being in bright sunlight, it takes some time for our eyes to adjust to the new light level. This process is known as dark adaptation.

5. Aging-related adaptations: As we age, various physiological changes occur that help us adapt to the changing environment and maintain homeostasis. These include changes in body composition, immune function, and cognitive abilities.

Optic nerve neoplasms refer to abnormal growths or tumors that develop within or near the optic nerve. These tumors can be benign (non-cancerous) or malignant (cancerous).

Benign optic nerve neoplasms include optic nerve meningiomas and schwannomas, which originate from the sheaths surrounding the optic nerve. They usually grow slowly and may not cause significant vision loss, but they can lead to compression of the optic nerve, resulting in visual field defects or optic disc swelling (papilledema).

Malignant optic nerve neoplasms are rare but more aggressive. The most common type is optic nerve glioma, which arises from the glial cells within the optic nerve. These tumors can quickly damage the optic nerve and cause severe vision loss.

It's important to note that any optic nerve neoplasm requires prompt medical evaluation and treatment, as they can potentially lead to significant visual impairment or even blindness if left untreated.

Retinoscopy is a diagnostic technique used in optometry and ophthalmology to estimate the refractive error of the eye, or in other words, to determine the prescription for eyeglasses or contact lenses. This procedure involves shining a light into the patient's pupil and observing the reflection off the retina while introducing different lenses in front of the patient's eye. The examiner then uses specific movements and observations to determine the amount and type of refractive error, such as myopia (nearsightedness), hyperopia (farsightedness), astigmatism, or presbyopia. Retinoscopy is a fundamental skill for eye care professionals and helps ensure that patients receive accurate prescriptions for corrective lenses.

A cataract is a clouding of the natural lens in the eye that affects vision. This clouding can cause vision to become blurry, faded, or dim, making it difficult to see clearly. Cataracts are a common age-related condition, but they can also be caused by injury, disease, or medication use. In most cases, cataracts develop gradually over time and can be treated with surgery to remove the cloudy lens and replace it with an artificial one.

Anterior Temporal Lobectomy is a surgical procedure that involves the removal of a portion of the anterior (front) part of the temporal lobe of the brain. This procedure is often performed to treat certain types of epilepsy that are resistant to medication, as well as other conditions such as tumors or degenerative diseases that affect this area of the brain.

The temporal lobe is located on each side of the brain and is involved in several important functions, including hearing, memory, emotion, and language comprehension. The anterior portion of the temporal lobe contains structures such as the amygdala and hippocampus, which are critical for the formation and retrieval of memories.

During an anterior temporal lobectomy, a neurosurgeon will make an incision in the skull and remove a portion of the brain tissue that is causing seizures or other symptoms. The size and location of the resection will depend on the specific condition being treated and the individual patient's needs. After the surgery, patients may require rehabilitation to help them recover from any cognitive or physical deficits caused by the procedure.

Retrospective studies, also known as retrospective research or looking back studies, are a type of observational study that examines data from the past to draw conclusions about possible causal relationships between risk factors and outcomes. In these studies, researchers analyze existing records, medical charts, or previously collected data to test a hypothesis or answer a specific research question.

Retrospective studies can be useful for generating hypotheses and identifying trends, but they have limitations compared to prospective studies, which follow participants forward in time from exposure to outcome. Retrospective studies are subject to biases such as recall bias, selection bias, and information bias, which can affect the validity of the results. Therefore, retrospective studies should be interpreted with caution and used primarily to generate hypotheses for further testing in prospective studies.

In medical terms, the face refers to the front part of the head that is distinguished by the presence of the eyes, nose, and mouth. It includes the bones of the skull (frontal bone, maxilla, zygoma, nasal bones, lacrimal bones, palatine bones, inferior nasal conchae, and mandible), muscles, nerves, blood vessels, skin, and other soft tissues. The face plays a crucial role in various functions such as breathing, eating, drinking, speaking, seeing, smelling, and expressing emotions. It also serves as an important identifier for individuals, allowing them to be recognized by others.

Electroencephalography (EEG) is a medical procedure that records electrical activity in the brain. It uses small, metal discs called electrodes, which are attached to the scalp with paste or a specialized cap. These electrodes detect tiny electrical charges that result from the activity of brain cells, and the EEG machine then amplifies and records these signals.

EEG is used to diagnose various conditions related to the brain, such as seizures, sleep disorders, head injuries, infections, and degenerative diseases like Alzheimer's or Parkinson's. It can also be used during surgery to monitor brain activity and ensure that surgical procedures do not interfere with vital functions.

EEG is a safe and non-invasive procedure that typically takes about 30 minutes to an hour to complete, although longer recordings may be necessary in some cases. Patients are usually asked to relax and remain still during the test, as movement can affect the quality of the recording.

An action potential is a brief electrical signal that travels along the membrane of a nerve cell (neuron) or muscle cell. It is initiated by a rapid, localized change in the permeability of the cell membrane to specific ions, such as sodium and potassium, resulting in a rapid influx of sodium ions and a subsequent efflux of potassium ions. This ion movement causes a brief reversal of the electrical potential across the membrane, which is known as depolarization. The action potential then propagates along the cell membrane as a wave, allowing the electrical signal to be transmitted over long distances within the body. Action potentials play a crucial role in the communication and functioning of the nervous system and muscle tissue.

In the context of medicine and healthcare, learning is often discussed in relation to learning abilities or disabilities that may impact an individual's capacity to acquire, process, retain, and apply new information or skills. Learning can be defined as the process of acquiring knowledge, understanding, behaviors, and skills through experience, instruction, or observation.

Learning disorders, also known as learning disabilities, are a type of neurodevelopmental disorder that affects an individual's ability to learn and process information in one or more areas, such as reading, writing, mathematics, or reasoning. These disorders are not related to intelligence or motivation but rather result from differences in the way the brain processes information.

It is important to note that learning can also be influenced by various factors, including age, cognitive abilities, physical and mental health status, cultural background, and educational experiences. Therefore, a comprehensive assessment of an individual's learning abilities and needs should take into account these various factors to provide appropriate support and interventions.

I'm sorry for the confusion, but "telescopes" is not a medical term. A telescope is an optical instrument that makes distant objects appear closer and larger by using an arrangement of lenses or mirrors and curved surfaces to gather and focus light. It is commonly used in astronomy to observe celestial bodies. If you have any questions related to medical terminology, I would be happy to help!

Optokinetic nystagmus (OKN) is a type of involuntary eye movement that occurs in response to large moving visual patterns. It serves as a mechanism for stabilizing the image on the retina during head movement and helps in maintaining visual fixation.

In OKN, there are two phases of eye movement: a slow phase where the eyes follow or track the moving pattern, and a fast phase where the eyes quickly reset to the starting position. This results in a back-and-forth or "to-and-fro" motion of the eyes.

Optokinetic nystagmus can be elicited by observing a large moving object or a series of alternating visual stimuli, such as stripes on a rotating drum. It is often used in clinical settings to assess various aspects of the visual system, including oculomotor function and visual acuity.

Abnormalities in OKN can indicate problems with the vestibular system, brainstem, or cerebellum, and may be associated with conditions such as brain injury, multiple sclerosis, or cerebral palsy.

Evoked potentials (EPs) are medical tests that measure the electrical activity in the brain or spinal cord in response to specific sensory stimuli, such as sight, sound, or touch. These tests are often used to help diagnose and monitor conditions that affect the nervous system, such as multiple sclerosis, brainstem tumors, and spinal cord injuries.

There are several types of EPs, including:

1. Visual Evoked Potentials (VEPs): These are used to assess the function of the visual pathway from the eyes to the back of the brain. A patient is typically asked to look at a patterned image or flashing light while electrodes placed on the scalp record the electrical responses.
2. Brainstem Auditory Evoked Potentials (BAEPs): These are used to evaluate the function of the auditory nerve and brainstem. Clicking sounds are presented to one or both ears, and electrodes placed on the scalp measure the response.
3. Somatosensory Evoked Potentials (SSEPs): These are used to assess the function of the peripheral nerves and spinal cord. Small electrical shocks are applied to a nerve at the wrist or ankle, and electrodes placed on the scalp record the response as it travels up the spinal cord to the brain.
4. Motor Evoked Potentials (MEPs): These are used to assess the function of the motor pathways in the brain and spinal cord. A magnetic or electrical stimulus is applied to the brain or spinal cord, and electrodes placed on a muscle measure the response as it travels down the motor pathway.

EPs can help identify abnormalities in the nervous system that may not be apparent through other diagnostic tests, such as imaging studies or clinical examinations. They are generally safe, non-invasive procedures with few risks or side effects.

Acoustic stimulation refers to the use of sound waves or vibrations to elicit a response in an individual, typically for the purpose of assessing or treating hearing, balance, or neurological disorders. In a medical context, acoustic stimulation may involve presenting pure tones, speech sounds, or other types of auditory signals through headphones, speakers, or specialized devices such as bone conduction transducers.

The response to acoustic stimulation can be measured using various techniques, including electrophysiological tests like auditory brainstem responses (ABRs) or otoacoustic emissions (OAEs), behavioral observations, or functional imaging methods like fMRI. Acoustic stimulation is also used in therapeutic settings, such as auditory training programs for hearing impairment or vestibular rehabilitation for balance disorders.

It's important to note that acoustic stimulation should be administered under the guidance of a qualified healthcare professional to ensure safety and effectiveness.

I'm sorry for any confusion, but "Linear Models" is actually a term from the field of statistics and machine learning, rather than medicine. A linear model is a type of statistical model that is used to analyze the relationship between two or more variables. In a linear model, the relationship between the dependent variable (the outcome or result) and the independent variable(s) (the factors being studied) is assumed to be linear, meaning that it can be described by a straight line on a graph.

The equation for a simple linear model with one independent variable (x) and one dependent variable (y) looks like this:

y = β0 + β1*x + ε

In this equation, β0 is the y-intercept or the value of y when x equals zero, β1 is the slope or the change in y for each unit increase in x, and ε is the error term or the difference between the actual values of y and the predicted values of y based on the linear model.

Linear models are widely used in medical research to study the relationship between various factors (such as exposure to a risk factor or treatment) and health outcomes (such as disease incidence or mortality). They can also be used to adjust for confounding variables, which are factors that may influence both the independent variable and the dependent variable, and thus affect the observed relationship between them.

In the context of medicine, particularly in anatomy and physiology, "rotation" refers to the movement of a body part around its own axis or the long axis of another structure. This type of motion is three-dimensional and can occur in various planes. A common example of rotation is the movement of the forearm bones (radius and ulna) around each other during pronation and supination, which allows the hand to be turned palm up or down. Another example is the rotation of the head during mastication (chewing), where the mandible moves in a circular motion around the temporomandibular joint.

"Macaca fascicularis" is the scientific name for the crab-eating macaque, also known as the long-tailed macaque. It's a species of monkey that is native to Southeast Asia. They are called "crab-eating" macaques because they are known to eat crabs and other crustaceans. These monkeys are omnivorous and their diet also includes fruits, seeds, insects, and occasionally smaller vertebrates.

Crab-eating macaques are highly adaptable and can be found in a wide range of habitats, including forests, grasslands, and wetlands. They are also known to live in close proximity to human settlements and are often considered pests due to their tendency to raid crops and steal food from humans.

These monkeys are social animals and live in large groups called troops. They have a complex social structure with a clear hierarchy and dominant males. Crab-eating macaques are also known for their intelligence and problem-solving abilities.

In medical research, crab-eating macaques are often used as animal models due to their close genetic relationship to humans. They are used in studies related to infectious diseases, neuroscience, and reproductive biology, among others.

The posterior thalamic nuclei are a group of nuclei located in the dorsal part of the thalamus, a major relay center in the brain. These nuclei include the lateroposterior nucleus (LP), pulvinar, and the medial and lateral geniculate bodies (MGN, LGN). They play crucial roles in processing and integrating sensory information, particularly from visual and auditory pathways, as well as motor and cognitive functions.

1. Lateroposterior nucleus (LP): This nucleus is involved in the processing of somatosensory information, which includes touch, pain, temperature, and proprioception (body position sense). It receives input from the cerebellum and sends outputs to the parietal cortex, contributing to the perception of body movement and position.

2. Pulvinar: The pulvinar is the largest nucleus in the thalamus and is primarily involved in visual processing. It receives inputs from multiple sources, including the retina, superior colliculus, and visual cortex, and sends outputs to various areas of the visual cortex. The pulvinar plays a critical role in attentional selection, object recognition, and scene perception.

3. Medial geniculate body (MGN): This nucleus is a part of the auditory pathway and receives input from the inferior colliculus in the midbrain. The MGN sends outputs to the primary auditory cortex, where sound processing and interpretation occur.

4. Lateral geniculate body (LGN): The LGN is a critical component of the visual pathway, receiving direct input from the retina and sending outputs to the primary visual cortex. It contains six layers, with alternating ON and OFF layers that process information from corresponding regions of the visual field.

In summary, the posterior thalamic nuclei are essential for sensory processing, attention, and perception in various modalities, including vision, audition, and somatosensation.

Aberrometry is a medical diagnostic technique used to measure the amount and type of aberration or distortion in the optical system of the eye. It is often used to evaluate the quality of vision, particularly in cases where traditional methods of measuring visual acuity are not sufficient.

During an aberrometry test, the patient looks into a specialized instrument called a wavefront sensor while a series of light patterns are projected onto the retina. The sensor then measures how the light is distorted as it passes through the eye's optical system, including the cornea and lens. This information is used to create a detailed map of the eye's aberrations, which can help doctors identify any irregularities that may be contributing to visual symptoms such as blurred vision, glare, or halos around lights.

Aberrometry is often used in conjunction with other diagnostic tests to evaluate patients who are considering refractive surgery, such as LASIK or PRK. By identifying any abnormalities in the eye's optical system, doctors can determine whether a patient is a good candidate for surgery and make more informed decisions about how to proceed with treatment.

Discrimination learning is a type of learning in which an individual learns to distinguish between two or more stimuli and respond differently to each. It involves the ability to recognize the differences between similar stimuli and to respond appropriately based on the specific characteristics of each stimulus. This type of learning is important for many aspects of cognition, including perception, language, and problem-solving.

In discrimination learning, an individual may be presented with two or more stimuli and reinforced for responding differently to each. For example, a person might be trained to press a button in response to the color red and to do nothing in response to the color green. Through this process of differential reinforcement, the individual learns to discriminate between the two colors and to respond appropriately to each.

Discrimination learning is often studied in animals as well as humans, and it is thought to involve a range of cognitive processes, including attention, memory, and perception. It is an important aspect of many forms of learning and plays a role in a wide variety of behaviors.

Aging is a complex, progressive and inevitable process of bodily changes over time, characterized by the accumulation of cellular damage and degenerative changes that eventually lead to increased vulnerability to disease and death. It involves various biological, genetic, environmental, and lifestyle factors that contribute to the decline in physical and mental functions. The medical field studies aging through the discipline of gerontology, which aims to understand the underlying mechanisms of aging and develop interventions to promote healthy aging and extend the human healthspan.

Perceptual closure, also known as "closure perception" or "gestalt perception," is not a term that has a specific medical definition. It is a concept in the field of psychology and perception, particularly in gestalt psychology.

Perceptual closure refers to the ability of the brain to recognize and complete incomplete patterns or shapes by filling in the missing information based on context and past experiences. This allows us to perceive and understand complex stimuli even when they are partially occluded, distorted, or incomplete. It is a fundamental aspect of how we process visual information and helps us quickly and efficiently make sense of our environment.

While there may not be a specific medical definition for perceptual closure, deficits in this ability can have implications for various medical conditions, such as neurological disorders that affect vision or cognitive function.

Computer-assisted diagnosis (CAD) is the use of computer systems to aid in the diagnostic process. It involves the use of advanced algorithms and data analysis techniques to analyze medical images, laboratory results, and other patient data to help healthcare professionals make more accurate and timely diagnoses. CAD systems can help identify patterns and anomalies that may be difficult for humans to detect, and they can provide second opinions and flag potential errors or uncertainties in the diagnostic process.

CAD systems are often used in conjunction with traditional diagnostic methods, such as physical examinations and patient interviews, to provide a more comprehensive assessment of a patient's health. They are commonly used in radiology, pathology, cardiology, and other medical specialties where imaging or laboratory tests play a key role in the diagnostic process.

While CAD systems can be very helpful in the diagnostic process, they are not infallible and should always be used as a tool to support, rather than replace, the expertise of trained healthcare professionals. It's important for medical professionals to use their clinical judgment and experience when interpreting CAD results and making final diagnoses.

Vision disparity, also known as binocular vision disparity, refers to the difference in the image that is perceived by each eye. This can occur due to a variety of reasons such as misalignment of the eyes (strabismus), unequal refractive power in each eye (anisometropia), or abnormalities in the shape of the eye (astigmatism).

When there is a significant difference in the image that is perceived by each eye, the brain may have difficulty combining the two images into a single, three-dimensional perception. This can result in visual symptoms such as double vision (diplopia), eyestrain, headaches, and difficulty with depth perception.

Vision disparity can be detected through a comprehensive eye examination and may be treated with corrective lenses, prism lenses, vision therapy, or surgery, depending on the underlying cause and severity of the condition.

The brain is the central organ of the nervous system, responsible for receiving and processing sensory information, regulating vital functions, and controlling behavior, movement, and cognition. It is divided into several distinct regions, each with specific functions:

1. Cerebrum: The largest part of the brain, responsible for higher cognitive functions such as thinking, learning, memory, language, and perception. It is divided into two hemispheres, each controlling the opposite side of the body.
2. Cerebellum: Located at the back of the brain, it is responsible for coordinating muscle movements, maintaining balance, and fine-tuning motor skills.
3. Brainstem: Connects the cerebrum and cerebellum to the spinal cord, controlling vital functions such as breathing, heart rate, and blood pressure. It also serves as a relay center for sensory information and motor commands between the brain and the rest of the body.
4. Diencephalon: A region that includes the thalamus (a major sensory relay station) and hypothalamus (regulates hormones, temperature, hunger, thirst, and sleep).
5. Limbic system: A group of structures involved in emotional processing, memory formation, and motivation, including the hippocampus, amygdala, and cingulate gyrus.

The brain is composed of billions of interconnected neurons that communicate through electrical and chemical signals. It is protected by the skull and surrounded by three layers of membranes called meninges, as well as cerebrospinal fluid that provides cushioning and nutrients.

Scanning Laser Polarimetry (SLP) is not primarily a medical term, but a technique that has been applied in medical research and diagnostics. It's a non-invasive method used to analyze the polarization of light as it interacts with biological tissues.

In a simpler sense, SLP uses laser light, which is polarized (meaning all the light waves vibrate in the same plane), to scan tissue. As this light interacts with the tissue, changes in the polarization of the light can occur due to various factors such as the structure and composition of the tissue. By analyzing these changes, SLP can provide information about the tissue's properties, which can be useful in the detection and diagnosis of certain medical conditions.

For example, it has been used in research related to diagnosing diseases like glaucoma and Alzheimer's disease by analyzing the polarization changes in the eye's retina and the brain's cortex, respectively. However, it's important to note that while SLP has shown promise in these areas, it is not yet widely used in clinical settings.

Cataract extraction is a surgical procedure that involves removing the cloudy lens (cataract) from the eye. This procedure is typically performed to restore vision impairment caused by cataracts and improve overall quality of life. There are two primary methods for cataract extraction:

1. Phacoemulsification: This is the most common method used today. It involves making a small incision in the front part of the eye (cornea), inserting an ultrasonic probe to break up the cloudy lens into tiny pieces, and then removing those pieces with suction. After removing the cataract, an artificial intraocular lens (IOL) is inserted to replace the natural lens and help focus light onto the retina.

2. Extracapsular Cataract Extraction: In this method, a larger incision is made on the side of the cornea, allowing the surgeon to remove the cloudy lens in one piece without breaking it up. The back part of the lens capsule is left intact to support the IOL. This technique is less common and typically reserved for more advanced cataracts or when phacoemulsification cannot be performed.

Recovery from cataract extraction usually involves using eye drops to prevent infection and inflammation, as well as protecting the eye with a shield or glasses during sleep for a few weeks after surgery. Most people experience improved vision within a few days to a week following the procedure.

Agnosia is a medical term that refers to the inability to recognize or comprehend the meaning or significance of sensory stimuli, even though the specific senses themselves are intact. It is a higher-level cognitive disorder, caused by damage to certain areas of the brain that are responsible for processing and interpreting information from our senses.

There are different types of agnosia, depending on which sense is affected:

* Visual agnosia: The inability to recognize or identify objects, faces, or shapes based on visual input.
* Auditory agnosia: The inability to understand spoken language or recognize sounds, even though hearing is intact.
* Tactile agnosia: The inability to recognize objects by touch, despite normal tactile sensation.
* Olfactory and gustatory agnosia: The inability to identify smells or tastes, respectively, even though the senses of smell and taste are functioning normally.

Agnosia can result from various causes, including stroke, brain injury, infection, degenerative diseases, or tumors that damage specific areas of the brain involved in sensory processing and interpretation. Treatment for agnosia typically focuses on rehabilitation and compensation strategies to help individuals adapt to their deficits and improve their quality of life.

In the context of medical terminology, I believe you may be referring to "pursuit" as it relates to neurological tests. A smooth pursuit is a type of eye movement in which the eyes smoothly and slowly follow a moving object. It requires coordination between the extraocular muscles, vestibular system, and visual system. If there are issues with any of these systems, smooth pursuit can be affected, leading to abnormalities such as jerky or saccadic movements.

Therefore, "smooth pursuit" is a medical term used to describe the normal, coordinated movement of the eyes that allows for the tracking of moving objects in a smooth and continuous manner.

Timolol is a non-selective beta blocker drug that is primarily used to treat hypertension, angina pectoris, and glaucoma. It works by blocking the action of certain hormones such as epinephrine (adrenaline) on the heart and blood vessels, which helps to lower heart rate, reduce the force of heart muscle contraction, and decrease blood vessel constriction. These effects can help to lower blood pressure, reduce the workload on the heart, and improve oxygen supply to the heart muscle. In glaucoma treatment, timolol reduces the production of aqueous humor in the eye, thereby decreasing intraocular pressure.

The medical definition of Timolol is:

Timolol (tim-oh-lol) is a beta-adrenergic receptor antagonist used to treat hypertension, angina pectoris, and glaucoma. It works by blocking the action of epinephrine on the heart and blood vessels, which results in decreased heart rate, reduced force of heart muscle contraction, and decreased blood vessel constriction. In glaucoma treatment, timolol reduces aqueous humor production, thereby decreasing intraocular pressure. Timolol is available as an oral tablet, solution for injection, and ophthalmic solution.

The cerebral cortex is the outermost layer of the brain, characterized by its intricate folded structure and wrinkled appearance. It is a region of great importance as it plays a key role in higher cognitive functions such as perception, consciousness, thought, memory, language, and attention. The cerebral cortex is divided into two hemispheres, each containing four lobes: the frontal, parietal, temporal, and occipital lobes. These areas are responsible for different functions, with some regions specializing in sensory processing while others are involved in motor control or associative functions. The cerebral cortex is composed of gray matter, which contains neuronal cell bodies, and is covered by a layer of white matter that consists mainly of myelinated nerve fibers.

A computer simulation is a process that involves creating a model of a real-world system or phenomenon on a computer and then using that model to run experiments and make predictions about how the system will behave under different conditions. In the medical field, computer simulations are used for a variety of purposes, including:

1. Training and education: Computer simulations can be used to create realistic virtual environments where medical students and professionals can practice their skills and learn new procedures without risk to actual patients. For example, surgeons may use simulation software to practice complex surgical techniques before performing them on real patients.
2. Research and development: Computer simulations can help medical researchers study the behavior of biological systems at a level of detail that would be difficult or impossible to achieve through experimental methods alone. By creating detailed models of cells, tissues, organs, or even entire organisms, researchers can use simulation software to explore how these systems function and how they respond to different stimuli.
3. Drug discovery and development: Computer simulations are an essential tool in modern drug discovery and development. By modeling the behavior of drugs at a molecular level, researchers can predict how they will interact with their targets in the body and identify potential side effects or toxicities. This information can help guide the design of new drugs and reduce the need for expensive and time-consuming clinical trials.
4. Personalized medicine: Computer simulations can be used to create personalized models of individual patients based on their unique genetic, physiological, and environmental characteristics. These models can then be used to predict how a patient will respond to different treatments and identify the most effective therapy for their specific condition.

Overall, computer simulations are a powerful tool in modern medicine, enabling researchers and clinicians to study complex systems and make predictions about how they will behave under a wide range of conditions. By providing insights into the behavior of biological systems at a level of detail that would be difficult or impossible to achieve through experimental methods alone, computer simulations are helping to advance our understanding of human health and disease.

A "false positive reaction" in medical testing refers to a situation where a diagnostic test incorrectly indicates the presence of a specific condition or disease in an individual who does not actually have it. This occurs when the test results give a positive outcome, while the true health status of the person is negative or free from the condition being tested for.

False positive reactions can be caused by various factors including:

1. Presence of unrelated substances that interfere with the test result (e.g., cross-reactivity between similar molecules).
2. Low specificity of the test, which means it may detect other conditions or irrelevant factors as positive.
3. Contamination during sample collection, storage, or analysis.
4. Human errors in performing or interpreting the test results.

False positive reactions can have significant consequences, such as unnecessary treatments, anxiety, and increased healthcare costs. Therefore, it is essential to confirm any positive test result with additional tests or clinical evaluations before making a definitive diagnosis.

Pituitary apoplexy is a medical emergency that involves bleeding into the pituitary gland (a small gland at the base of the brain) and/or sudden swelling of the pituitary gland. This can lead to compression of nearby structures, such as the optic nerves and the hypothalamus, causing symptoms like severe headache, visual disturbances, hormonal imbalances, and altered mental status. It is often associated with a pre-existing pituitary tumor (such as a pituitary adenoma), but can also occur in individuals without any known pituitary abnormalities. Immediate medical attention is required to manage this condition, which may include surgical intervention, hormone replacement therapy, and supportive care.

In the context of medical and clinical neuroscience, memory is defined as the brain's ability to encode, store, retain, and recall information or experiences. Memory is a complex cognitive process that involves several interconnected regions of the brain and can be categorized into different types based on various factors such as duration and the nature of the information being remembered.

The major types of memory include:

1. Sensory memory: The shortest form of memory, responsible for holding incoming sensory information for a brief period (less than a second to several seconds) before it is either transferred to short-term memory or discarded.
2. Short-term memory (also called working memory): A temporary storage system that allows the brain to hold and manipulate information for approximately 20-30 seconds, although this duration can be extended through rehearsal strategies. Short-term memory has a limited capacity, typically thought to be around 7±2 items.
3. Long-term memory: The memory system responsible for storing large amounts of information over extended periods, ranging from minutes to a lifetime. Long-term memory has a much larger capacity compared to short-term memory and is divided into two main categories: explicit (declarative) memory and implicit (non-declarative) memory.

Explicit (declarative) memory can be further divided into episodic memory, which involves the recollection of specific events or episodes, including their temporal and spatial contexts, and semantic memory, which refers to the storage and retrieval of general knowledge, facts, concepts, and vocabulary, independent of personal experience or context.

Implicit (non-declarative) memory encompasses various forms of learning that do not require conscious awareness or intention, such as procedural memory (skills and habits), priming (facilitated processing of related stimuli), classical conditioning (associative learning), and habituation (reduced responsiveness to repeated stimuli).

Memory is a crucial aspect of human cognition and plays a significant role in various aspects of daily life, including learning, problem-solving, decision-making, social interactions, and personal identity. Memory dysfunction can result from various neurological and psychiatric conditions, such as dementia, Alzheimer's disease, stroke, traumatic brain injury, and depression.

Automation in the medical context refers to the use of technology and programming to allow machines or devices to operate with minimal human intervention. This can include various types of medical equipment, such as laboratory analyzers, imaging devices, and robotic surgical systems. Automation can help improve efficiency, accuracy, and safety in healthcare settings by reducing the potential for human error and allowing healthcare professionals to focus on higher-level tasks. It is important to note that while automation has many benefits, it is also essential to ensure that appropriate safeguards are in place to prevent accidents and maintain quality of care.

Nerve compression syndromes refer to a group of conditions characterized by the pressure or irritation of a peripheral nerve, causing various symptoms such as pain, numbness, tingling, and weakness in the affected area. This compression can occur due to several reasons, including injury, repetitive motion, bone spurs, tumors, or swelling. Common examples of nerve compression syndromes include carpal tunnel syndrome, cubital tunnel syndrome, radial nerve compression, and ulnar nerve entrapment at the wrist or elbow. Treatment options may include physical therapy, splinting, medications, injections, or surgery, depending on the severity and underlying cause of the condition.

In psychology, Signal Detection Theory (SDT) is a framework used to understand the ability to detect the presence or absence of a signal (such as a stimulus or event) in the presence of noise or uncertainty. It is often applied in sensory perception research, such as hearing and vision, where it helps to separate an observer's sensitivity to the signal from their response bias.

SDT involves measuring both hits (correct detections of the signal) and false alarms (incorrect detections when no signal is present). These measures are then used to calculate measures such as d', which reflects the observer's ability to discriminate between the signal and noise, and criterion (C), which reflects the observer's response bias.

SDT has been applied in various fields of psychology, including cognitive psychology, clinical psychology, and neuroscience, to study decision-making, memory, attention, and perception. It is a valuable tool for understanding how people make decisions under uncertainty and how they trade off accuracy and caution in their responses.

Eye movement measurements, also known as oculometry, refer to the measurement and analysis of eye movements. This can include assessing the direction, speed, range, and patterns of eye movement. These measurements are often used in research and clinical settings to understand various aspects of vision, perception, and cognition. They can be used to diagnose and monitor conditions that affect eye movement, such as strabismus (crossed eyes), amblyopia (lazy eye), or neurological disorders. Additionally, eye movement measurements are also used in areas such as human-computer interaction, marketing research, and virtual reality to understand how individuals interact with their environment.

A vitrectomy is a surgical procedure that involves the removal of some or all of the vitreous humor, which is the clear gel-like substance filling the center of the eye. This surgery is often performed to treat various retinal disorders such as diabetic retinopathy, retinal detachment, macular hole, and vitreous hemorrhage.

During a vitrectomy, the ophthalmologist makes small incisions in the sclera (the white part of the eye) to access the vitreous cavity. The surgeon then uses specialized instruments to remove the cloudy or damaged vitreous and may also repair any damage to the retina or surrounding tissues. Afterward, a clear saline solution is injected into the eye to maintain its shape and help facilitate healing.

In some cases, a gas bubble or silicone oil may be placed in the eye after the vitrectomy to help hold the retina in place while it heals. These substances will gradually be absorbed or removed during follow-up appointments. The body naturally produces a new, clear vitreous to replace the removed material over time.

Vitrectomy is typically performed under local anesthesia and may require hospitalization or outpatient care depending on the individual case. Potential risks and complications include infection, bleeding, cataract formation, retinal detachment, and increased eye pressure. However, with proper care and follow-up, most patients experience improved vision after a successful vitrectomy procedure.

Intraocular injections are a type of medical procedure where medication is administered directly into the eye. This technique is often used to deliver drugs that treat various eye conditions, such as age-related macular degeneration, diabetic retinopathy, and endophthalmitis. The most common type of intraocular injection is an intravitreal injection, which involves injecting medication into the vitreous cavity, the space inside the eye filled with a clear gel-like substance called the vitreous humor. This procedure is typically performed by an ophthalmologist in a clinical setting and may be repeated at regular intervals depending on the condition being treated.

Sensory aids are devices or equipment that are used to improve or compensate for impaired sensory functions such as hearing, vision, or touch. They are designed to help individuals with disabilities or impairments to better interact with their environment and perform daily activities. Here are some examples:

1. Hearing aids - electronic devices worn in or behind the ear that amplify sounds for people with hearing loss.
2. Cochlear implants - surgically implanted devices that provide sound sensations to individuals with severe to profound hearing loss.
3. Visual aids - devices used to improve vision, such as eyeglasses, contact lenses, magnifiers, or telescopic lenses.
4. Low vision devices - specialized equipment for people with significant visual impairment, including large print books, talking watches, and screen readers.
5. Tactile aids - devices that provide tactile feedback to individuals with visual or hearing impairments, such as Braille displays or vibrating pagers.

Overall, sensory aids play an essential role in enhancing the quality of life for people with sensory impairments by improving their ability to communicate, access information, and navigate their environment.

Anticonvulsants are a class of drugs used primarily to treat seizure disorders, also known as epilepsy. These medications work by reducing the abnormal electrical activity in the brain that leads to seizures. In addition to their use in treating epilepsy, anticonvulsants are sometimes also prescribed for other conditions, such as neuropathic pain, bipolar disorder, and migraine headaches.

Anticonvulsants can work in different ways to reduce seizure activity. Some medications, such as phenytoin and carbamazepine, work by blocking sodium channels in the brain, which helps to stabilize nerve cell membranes and prevent excessive electrical activity. Other medications, such as valproic acid and gabapentin, increase the levels of a neurotransmitter called gamma-aminobutyric acid (GABA) in the brain, which has a calming effect on nerve cells and helps to reduce seizure activity.

While anticonvulsants are generally effective at reducing seizure frequency and severity, they can also have side effects, such as dizziness, drowsiness, and gastrointestinal symptoms. In some cases, these side effects may be managed by adjusting the dosage or switching to a different medication. It is important for individuals taking anticonvulsants to work closely with their healthcare provider to monitor their response to the medication and make any necessary adjustments.

In the context of medical terminology, "motion" generally refers to the act or process of moving or changing position. It can also refer to the range of movement of a body part or joint. However, there is no single specific medical definition for the term "motion." The meaning may vary depending on the context in which it is used.

Onchocerciasis, Ocular is a medical condition that specifically refers to the eye manifestations caused by the parasitic infection, Onchocerca volvulus. Also known as "river blindness," this disease is spread through the bite of infected blackflies.

Ocular onchocerciasis affects various parts of the eye, including the conjunctiva, cornea, iris, and retina. The infection can cause symptoms such as itching, burning, and redness of the eyes. Over time, it may lead to more serious complications like punctate keratitis (small, scattered opacities on the cornea), cataracts, glaucoma, and ultimately, blindness.

The infection is diagnosed through a skin snip or blood test, which can detect the presence of microfilariae (the larval stage of the parasite) or antibodies against the parasite. Treatment typically involves administering oral medications such as ivermectin, which kills the microfilariae and reduces the risk of eye damage. However, it does not kill the adult worms, so multiple doses are often required to control the infection. In some cases, surgery may be necessary to remove advanced ocular lesions.

Neuronal plasticity, also known as neuroplasticity or neural plasticity, refers to the ability of the brain and nervous system to change and adapt as a result of experience, learning, injury, or disease. This can involve changes in the structure, organization, and function of neurons (nerve cells) and their connections (synapses) in the central and peripheral nervous systems.

Neuronal plasticity can take many forms, including:

* Synaptic plasticity: Changes in the strength or efficiency of synaptic connections between neurons. This can involve the formation, elimination, or modification of synapses.
* Neural circuit plasticity: Changes in the organization and connectivity of neural circuits, which are networks of interconnected neurons that process information.
* Structural plasticity: Changes in the physical structure of neurons, such as the growth or retraction of dendrites (branches that receive input from other neurons) or axons (projections that transmit signals to other neurons).
* Functional plasticity: Changes in the physiological properties of neurons, such as their excitability, responsiveness, or sensitivity to stimuli.

Neuronal plasticity is a fundamental property of the nervous system and plays a crucial role in many aspects of brain function, including learning, memory, perception, and cognition. It also contributes to the brain's ability to recover from injury or disease, such as stroke or traumatic brain injury.

In the context of medical terminology, "lenses" generally refers to optical lenses used in various medical devices and instruments. These lenses are typically made of glass or plastic and are designed to refract (bend) light in specific ways to help magnify, focus, or redirect images. Here are some examples:

1. In ophthalmology and optometry, lenses are used in eyeglasses, contact lenses, and ophthalmic instruments to correct vision problems like myopia (nearsightedness), hypermetropia (farsightedness), astigmatism, or presbyopia.
2. In surgical microscopes, lenses are used to provide a magnified and clear view of the operating field during microsurgical procedures like ophthalmic, neurosurgical, or ENT (Ear, Nose, Throat) surgeries.
3. In endoscopes and laparoscopes, lenses are used to transmit light and images from inside the body during minimally invasive surgical procedures.
4. In ophthalmic diagnostic instruments like slit lamps, lenses are used to examine various structures of the eye in detail.

In summary, "lenses" in medical terminology refer to optical components that help manipulate light to aid in diagnosis, treatment, or visual correction.

Electrophysiology is a branch of medicine that deals with the electrical activities of the body, particularly the heart. In a medical context, electrophysiology studies (EPS) are performed to assess abnormal heart rhythms (arrhythmias) and to evaluate the effectiveness of certain treatments, such as medication or pacemakers.

During an EPS, electrode catheters are inserted into the heart through blood vessels in the groin or neck. These catheters can record the electrical activity of the heart and stimulate it to help identify the source of the arrhythmia. The information gathered during the study can help doctors determine the best course of treatment for each patient.

In addition to cardiac electrophysiology, there are also other subspecialties within electrophysiology, such as neuromuscular electrophysiology, which deals with the electrical activity of the nervous system and muscles.

A Receiver Operating Characteristic (ROC) curve is a graphical representation used in medical decision-making and statistical analysis to illustrate the performance of a binary classifier system, such as a diagnostic test or a machine learning algorithm. It's a plot that shows the tradeoff between the true positive rate (sensitivity) and the false positive rate (1 - specificity) for different threshold settings.

The x-axis of an ROC curve represents the false positive rate (the proportion of negative cases incorrectly classified as positive), while the y-axis represents the true positive rate (the proportion of positive cases correctly classified as positive). Each point on the curve corresponds to a specific decision threshold, with higher points indicating better performance.

The area under the ROC curve (AUC) is a commonly used summary measure that reflects the overall performance of the classifier. An AUC value of 1 indicates perfect discrimination between positive and negative cases, while an AUC value of 0.5 suggests that the classifier performs no better than chance.

ROC curves are widely used in healthcare to evaluate diagnostic tests, predictive models, and screening tools for various medical conditions, helping clinicians make informed decisions about patient care based on the balance between sensitivity and specificity.

A craniopharyngioma is a type of brain tumor that develops near the pituitary gland, which is a small gland located at the base of the brain. These tumors arise from remnants of Rathke's pouch, an embryonic structure involved in the development of the pituitary gland.

Craniopharyngiomas are typically slow-growing and benign (non-cancerous), but they can still cause significant health problems due to their location. They can compress nearby structures such as the optic nerves, hypothalamus, and pituitary gland, leading to symptoms like vision loss, hormonal imbalances, and cognitive impairment.

Treatment for craniopharyngiomas usually involves surgical removal of the tumor, followed by radiation therapy in some cases. Regular follow-up with a healthcare team is essential to monitor for recurrence and manage any long-term effects of treatment.

An Expert System is a type of artificial intelligence (AI) program that emulates the decision-making ability of a human expert in a specific field or domain. It is designed to solve complex problems by using a set of rules, heuristics, and knowledge base derived from human expertise. The system can simulate the problem-solving process of a human expert, allowing it to provide advice, make recommendations, or diagnose problems in a similar manner. Expert systems are often used in fields such as medicine, engineering, finance, and law where specialized knowledge and experience are critical for making informed decisions.

The medical definition of 'Expert Systems' refers to AI programs that assist healthcare professionals in diagnosing and treating medical conditions, based on a large database of medical knowledge and clinical expertise. These systems can help doctors and other healthcare providers make more accurate diagnoses, recommend appropriate treatments, and provide patient education. They may also be used for research, training, and quality improvement purposes.

Expert systems in medicine typically use a combination of artificial intelligence techniques such as rule-based reasoning, machine learning, natural language processing, and pattern recognition to analyze medical data and provide expert advice. Examples of medical expert systems include MYCIN, which was developed to diagnose infectious diseases, and Internist-1, which assists in the diagnosis and management of internal medicine cases.

Reference values, also known as reference ranges or reference intervals, are the set of values that are considered normal or typical for a particular population or group of people. These values are often used in laboratory tests to help interpret test results and determine whether a patient's value falls within the expected range.

The process of establishing reference values typically involves measuring a particular biomarker or parameter in a large, healthy population and then calculating the mean and standard deviation of the measurements. Based on these statistics, a range is established that includes a certain percentage of the population (often 95%) and excludes extreme outliers.

It's important to note that reference values can vary depending on factors such as age, sex, race, and other demographic characteristics. Therefore, it's essential to use reference values that are specific to the relevant population when interpreting laboratory test results. Additionally, reference values may change over time due to advances in measurement technology or changes in the population being studied.

In the context of medicine and healthcare, "movement" refers to the act or process of changing physical location or position. It involves the contraction and relaxation of muscles, which allows for the joints to move and the body to be in motion. Movement can also refer to the ability of a patient to move a specific body part or limb, which is assessed during physical examinations. Additionally, "movement" can describe the progression or spread of a disease within the body.

The optic lobe in non-mammals refers to a specific region of the brain that is responsible for processing visual information. It is a part of the protocerebrum in the insect brain and is analogous to the mammalian visual cortex. The optic lobes receive input directly from the eyes via the optic nerves and are involved in the interpretation and integration of visual stimuli, enabling non-mammals to perceive and respond to their environment. In some invertebrates, like insects, the optic lobe is further divided into subregions, including the lamina, medulla, and lobula, each with distinct functions in visual processing.

Brain diseases, also known as neurological disorders, refer to a wide range of conditions that affect the brain and nervous system. These diseases can be caused by various factors such as genetics, infections, injuries, degeneration, or structural abnormalities. They can affect different parts of the brain, leading to a variety of symptoms and complications.

Some examples of brain diseases include:

1. Alzheimer's disease - a progressive degenerative disorder that affects memory and cognitive function.
2. Parkinson's disease - a movement disorder characterized by tremors, stiffness, and difficulty with coordination and balance.
3. Multiple sclerosis - a chronic autoimmune disease that affects the nervous system and can cause a range of symptoms such as vision loss, muscle weakness, and cognitive impairment.
4. Epilepsy - a neurological disorder characterized by recurrent seizures.
5. Brain tumors - abnormal growths in the brain that can be benign or malignant.
6. Stroke - a sudden interruption of blood flow to the brain, which can cause paralysis, speech difficulties, and other neurological symptoms.
7. Meningitis - an infection of the membranes surrounding the brain and spinal cord.
8. Encephalitis - an inflammation of the brain that can be caused by viruses, bacteria, or autoimmune disorders.
9. Huntington's disease - a genetic disorder that affects muscle coordination, cognitive function, and mental health.
10. Migraine - a neurological condition characterized by severe headaches, often accompanied by nausea, vomiting, and sensitivity to light and sound.

Brain diseases can range from mild to severe and may be treatable or incurable. They can affect people of all ages and backgrounds, and early diagnosis and treatment are essential for improving outcomes and quality of life.

A microelectrode is a small electrode with dimensions ranging from several micrometers to a few tens of micrometers in diameter. They are used in various biomedical applications, such as neurophysiological studies, neuromodulation, and brain-computer interfaces. In these applications, microelectrodes serve to record electrical activity from individual or small groups of neurons or deliver electrical stimuli to specific neural structures with high spatial resolution.

Microelectrodes can be fabricated using various materials, including metals (e.g., tungsten, stainless steel, platinum), metal alloys, carbon fibers, and semiconductor materials like silicon. The design of microelectrodes may vary depending on the specific application, with some common types being sharpened metal wires, glass-insulated metal microwires, and silicon-based probes with multiple recording sites.

The development and use of microelectrodes have significantly contributed to our understanding of neural function in health and disease, enabling researchers and clinicians to investigate the underlying mechanisms of neurological disorders and develop novel therapies for conditions such as Parkinson's disease, epilepsy, and hearing loss.

A nerve net, also known as a neural net or neuronal network, is not a medical term per se, but rather a concept in neuroscience and artificial intelligence (AI). It refers to a complex network of interconnected neurons that process and transmit information. In the context of the human body, the nervous system can be thought of as a type of nerve net, with the brain and spinal cord serving as the central processing unit and peripheral nerves carrying signals to and from various parts of the body.

In the field of AI, artificial neural networks are computational models inspired by the structure and function of biological nerve nets. These models consist of interconnected nodes or "neurons" that process information and learn patterns through a process of training and adaptation. They have been used in a variety of applications, including image recognition, natural language processing, and machine learning.

"Figural aftereffect" is not a widely recognized or established term in medical or clinical neuroscience literature. However, it seems to be related to the concept of "perceptual aftereffects," which are well-documented phenomena in visual and other sensory perception. Here's a definition that may help you understand figural aftereffects within this context:

Perceptual aftereffect is a phenomenon where exposure to a specific stimulus for a certain period can temporarily alter the perception of subsequent stimuli, making them appear different from what they would have been without the initial exposure. This effect arises due to neural adaptation in response to the prolonged exposure.

In the case of "figural aftereffect," it likely refers to a specific type of perceptual aftereffect where the perception of figures or shapes is affected by prior exposure. For example, if someone stares at a curved line for a while and then looks at a straight line, they might initially perceive the straight line as being more curved than it actually is due to the lingering influence of the initial stimulus.

However, since "figural aftereffect" isn't a standard term in medical or neuroscience literature, I would recommend consulting original research articles or experts in visual perception for a more precise definition and context.

Neuropsychological tests are a type of psychological assessment that measures cognitive functions, such as attention, memory, language, problem-solving, and perception. These tests are used to help diagnose and understand the cognitive impact of neurological conditions, including dementia, traumatic brain injury, stroke, Parkinson's disease, and other disorders that affect the brain.

The tests are typically administered by a trained neuropsychologist and can take several hours to complete. They may involve paper-and-pencil tasks, computerized tasks, or interactive activities. The results of the tests are compared to normative data to help identify any areas of cognitive weakness or strength.

Neuropsychological testing can provide valuable information for treatment planning, rehabilitation, and assessing response to treatment. It can also be used in research to better understand the neural basis of cognition and the impact of neurological conditions on cognitive function.

Interferometry is not specifically a medical term, but it is used in certain medical fields such as ophthalmology and optics research. Here is a general definition:

Interferometry is a physical method that uses the interference of waves to measure the differences in phase between two or more waves. In other words, it's a technique that combines two or more light waves to create an interference pattern, which can then be analyzed to extract information about the properties of the light waves, such as their wavelength, amplitude, and phase.

In ophthalmology, interferometry is used in devices like wavefront sensors to measure the aberrations in the eye's optical system. By analyzing the interference pattern created by the light passing through the eye, these devices can provide detailed information about the shape and curvature of the cornea and lens, helping doctors to diagnose and treat various vision disorders.

In optics research, interferometry is used to study the properties of light waves and materials that interact with them. By analyzing the interference patterns created by light passing through different materials or devices, researchers can gain insights into their optical properties, such as their refractive index, thickness, and surface roughness.

The corpus callosum is the largest collection of white matter in the brain, consisting of approximately 200 million nerve fibers. It is a broad, flat band of tissue that connects the two hemispheres of the brain, allowing them to communicate and coordinate information processing. The corpus callosum plays a crucial role in integrating sensory, motor, and cognitive functions between the two sides of the brain. Damage to the corpus callosum can result in various neurological symptoms, including difficulties with movement, speech, memory, and social behavior.

Auditory perception refers to the process by which the brain interprets and makes sense of the sounds we hear. It involves the recognition and interpretation of different frequencies, intensities, and patterns of sound waves that reach our ears through the process of hearing. This allows us to identify and distinguish various sounds such as speech, music, and environmental noises.

The auditory system includes the outer ear, middle ear, inner ear, and the auditory nerve, which transmits electrical signals to the brain's auditory cortex for processing and interpretation. Auditory perception is a complex process that involves multiple areas of the brain working together to identify and make sense of sounds in our environment.

Disorders or impairments in auditory perception can result in difficulties with hearing, understanding speech, and identifying environmental sounds, which can significantly impact communication, learning, and daily functioning.

'Task Performance and Analysis' is not a commonly used medical term, but it can be found in the field of rehabilitation medicine and ergonomics. It refers to the process of evaluating and understanding how a specific task is performed, in order to identify any physical or cognitive demands placed on an individual during the performance of that task. This information can then be used to inform the design of interventions, such as workplace modifications or rehabilitation programs, aimed at improving task performance or reducing the risk of injury.

In a medical context, task performance and analysis may be used in the assessment and treatment of individuals with disabilities or injuries, to help them return to work or other activities of daily living. The analysis involves breaking down the task into its component parts, observing and measuring the physical and cognitive demands of each part, and evaluating the individual's ability to perform those demands. Based on this analysis, recommendations may be made for modifications to the task or the environment, training or education, or assistive devices that can help the individual perform the task more safely and efficiently.

Overall, task performance and analysis is a valuable tool in promoting safe and effective task performance, reducing the risk of injury, and improving functional outcomes for individuals with disabilities or injuries.

Corneal pachymetry is a medical measurement of the thickness of the cornea, which is the clear, dome-shaped surface at the front of the eye. This measurement is typically taken using a specialized instrument called a pachymeter. The procedure is quick, painless, and non-invasive.

Corneal pachymetry is an essential test in optometry and ophthalmology for various reasons. For instance, it helps assess the overall health of the cornea, identify potential abnormalities or diseases, and determine the correct intraocular lens power during cataract surgery. Additionally, corneal thickness is a crucial factor in determining a person's risk for developing glaucoma and monitoring the progression of the disease.

In some cases, such as with contact lens fitting, corneal pachymetry can help ensure proper fit and minimize potential complications. Overall, corneal pachymetry is an essential diagnostic tool in eye care that provides valuable information for maintaining eye health and ensuring appropriate treatment.

Photoreceptor cells are specialized neurons in the retina of the eye that convert light into electrical signals. These cells consist of two types: rods and cones. Rods are responsible for vision at low light levels and provide black-and-white, peripheral, and motion sensitivity. Cones are active at higher light levels and are capable of color discrimination and fine detail vision. Both types of photoreceptor cells contain light-sensitive pigments that undergo chemical changes when exposed to light, triggering a series of electrical signals that ultimately reach the brain and contribute to visual perception.

Mercury poisoning, also known as hydrargyria or mercurialism, is a type of metal poisoning caused by exposure to mercury or its compounds. It can occur through inhalation, ingestion, or skin absorption. Symptoms may vary but can include sensory impairment (vision, hearing, speech), disturbed sensation and a lack of coordination. The type of symptoms can vary greatly, depending on the type and amount of mercury and the form in which it was taken. Long-term exposure to mercury can lead to serious neurological and kidney problems. It is usually diagnosed through tests that measure the amount of mercury in the body, such as blood or urine tests. Treatment generally involves eliminating the source of mercury exposure, supportive care, and, in some cases, chelation therapy which helps to remove mercury from the body.

Head movements refer to the voluntary or involuntary motion of the head in various directions. These movements can occur in different planes, including flexion (moving the head forward), extension (moving the head backward), rotation (turning the head to the side), and lateral bending (leaning the head to one side).

Head movements can be a result of normal physiological processes, such as when nodding in agreement or shaking the head to indicate disagreement. They can also be caused by neurological conditions, such as abnormal head movements in patients with Parkinson's disease or cerebellar disorders. Additionally, head movements may occur in response to sensory stimuli, such as turning the head toward a sound.

In a medical context, an examination of head movements can provide important clues about a person's neurological function and help diagnose various conditions affecting the brain and nervous system.

'Animal behavior' refers to the actions or responses of animals to various stimuli, including their interactions with the environment and other individuals. It is the study of the actions of animals, whether they are instinctual, learned, or a combination of both. Animal behavior includes communication, mating, foraging, predator avoidance, and social organization, among other things. The scientific study of animal behavior is called ethology. This field seeks to understand the evolutionary basis for behaviors as well as their physiological and psychological mechanisms.

Astigmatism is a common eye condition that occurs when the cornea or lens has an irregular shape, causing blurred or distorted vision. The cornea and lens are typically smooth and curved uniformly in all directions, allowing light to focus clearly on the retina. However, if the cornea or lens is not smoothly curved and has a steeper curve in one direction than the other, it causes light to focus unevenly on the retina, leading to astigmatism.

Astigmatism can cause blurred vision at all distances, as well as eye strain, headaches, and fatigue. It is often present from birth and can be hereditary, but it can also develop later in life due to eye injuries or surgery. Astigmatism can be corrected with glasses, contact lenses, or refractive surgery such as LASIK.

A ferret is a domesticated mammal that belongs to the weasel family, Mustelidae. The scientific name for the common ferret is Mustela putorius furo. Ferrets are native to Europe and have been kept as pets for thousands of years due to their playful and curious nature. They are small animals, typically measuring between 13-20 inches in length, including their tail, and weighing between 1.5-4 pounds.

Ferrets have a slender body with short legs, a long neck, and a pointed snout. They have a thick coat of fur that can vary in color from white to black, with many different patterns in between. Ferrets are known for their high level of activity and intelligence, and they require regular exercise and mental stimulation to stay healthy and happy.

Ferrets are obligate carnivores, which means that they require a diet that is high in protein and low in carbohydrates. They have a unique digestive system that allows them to absorb nutrients efficiently from their food, but it also means that they are prone to certain health problems if they do not receive proper nutrition.

Ferrets are social animals and typically live in groups. They communicate with each other using a variety of vocalizations, including barks, chirps, and purrs. Ferrets can be trained to use a litter box and can learn to perform simple tricks. With proper care and attention, ferrets can make loving and entertaining pets.

Retinal vessels refer to the blood vessels that are located in the retina, which is the light-sensitive tissue that lines the inner surface of the eye. The retina contains two types of blood vessels: arteries and veins.

The central retinal artery supplies oxygenated blood to the inner layers of the retina, while the central retinal vein drains deoxygenated blood from the retina. These vessels can be visualized during a routine eye examination using an ophthalmoscope, which allows healthcare professionals to assess their health and any potential abnormalities.

Retinal vessels are essential for maintaining the health and function of the retina, and any damage or changes to these vessels can affect vision and lead to various eye conditions such as diabetic retinopathy, retinal vein occlusion, and hypertensive retinopathy.

I am not aware of a medical definition for the term "darkness." In general, darkness refers to the absence of light. It is not a term that is commonly used in the medical field, and it does not have a specific clinical meaning. If you have a question about a specific medical term or concept, I would be happy to try to help you understand it.

In the context of medical definitions, "judgment" generally refers to the ability to make decisions or form opinions regarding a patient's condition or treatment. It involves critical thinking, clinical reasoning, and knowledge of medical principles and practices. In some cases, it may also refer to a medical professional's assessment or evaluation of a patient's health status or response to treatment.

However, it is important to note that "judgment" is not a term with a specific medical definition, and its meaning can vary depending on the context in which it is used. In general, it refers to the ability to make sound decisions based on evidence, experience, and expertise.

I'm sorry for any confusion, but "touch" is not a term that has a specific medical definition in the context you've provided. In a general sense, touch refers to the ability to perceive things through physically contacting them, which is a function of our nervous system. However, it's not a term used to describe a specific medical condition, diagnosis, treatment, or procedure. If you have any more specific context or question in mind, I'd be happy to try and help further!

Physiologic nystagmus is a type of normal, involuntary eye movement that occurs in certain situations. It is characterized by rhythmical to-and-fro movements of the eyes, which can be horizontal, vertical, or rotatory. The most common form of physiologic nystagmus is called "optokinetic nystagmus," which occurs when a person looks at a moving pattern, such as stripes on a rotating drum or scenery passing by a car window.

Optokinetic nystagmus helps to stabilize the image of the environment on the retina and allows the brain to perceive motion accurately. Another form of physiologic nystagmus is "pursuit nystagmus," which occurs when the eyes attempt to follow a slowly moving target. In this case, the eyes may overshoot the target and then make a corrective movement in the opposite direction.

Physiologic nystagmus is different from pathological nystagmus, which can be caused by various medical conditions such as brain damage, inner ear disorders, or medications that affect the nervous system. Pathological nystagmus may indicate a serious underlying condition and should be evaluated by a healthcare professional.

In medical terms, the "head" is the uppermost part of the human body that contains the brain, skull, face, eyes, nose, mouth, and ears. It is connected to the rest of the body by the neck and is responsible for many vital functions such as sight, hearing, smell, taste, touch, and thought processing. The head also plays a crucial role in maintaining balance, speech, and eating.

A retinal perforation is a full-thickness break or hole in the retina, which is the light-sensitive tissue that lines the inner surface of the eye. This condition can lead to a serious complication called retinal detachment, where the retina separates from the underlying tissue, potentially resulting in vision loss if not promptly treated. Retinal perforations may be caused by trauma, certain eye conditions, or invasive eye procedures. Immediate medical attention is required for retinal perforations to prevent further damage and preserve vision.

An afterimage is a visual phenomenon that occurs when the eye's retina continues to send signals to the brain even after exposure to a stimulus has ended. This can result in the perception of a lingering image, often in complementary colors to the original stimulus. Afterimages can be either positive or negative, with a positive afterimage appearing as the same color as the original stimulus and a negative afterimage appearing as its complementary color.

Afterimages are typically caused by exposure to bright or intense light sources, such as a camera flash or the sun. They can also occur after prolonged exposure to a particular color or pattern. The phenomenon is thought to be related to the adaptation of photoreceptor cells in the retina, which become less responsive to stimuli after prolonged exposure.

Afterimages are generally harmless and temporary, lasting only a few seconds to several minutes. However, they can sometimes be used as a tool for visual perception experiments or to study the mechanisms of visual processing in the brain.

Treatment outcome is a term used to describe the result or effect of medical treatment on a patient's health status. It can be measured in various ways, such as through symptoms improvement, disease remission, reduced disability, improved quality of life, or survival rates. The treatment outcome helps healthcare providers evaluate the effectiveness of a particular treatment plan and make informed decisions about future care. It is also used in clinical research to compare the efficacy of different treatments and improve patient care.

'Erigeron' is a genus of flowering plants in the daisy family, Asteraceae. It includes over 400 species that are commonly known as fleabanes or ragworts. These plants are native to North and South America, with some species found in Europe and Asia. They are herbaceous annuals, biennials, or perennials that typically grow between 15 cm to 60 cm tall. The flowers of Erigeron species are small and daisy-like, with a white, pink, purple, or blue ray florets surrounding a yellow or brown disk floret.

While 'Erigeron' is a genus of plants and not a medical term, some species have been used in traditional medicine for their alleged medicinal properties. For example, Erigeron canadensis (Canada fleabane) has been used to treat various conditions such as skin irritations, coughs, and colds. However, it is important to note that the use of Erigeron species for medicinal purposes should be done under the guidance of a healthcare professional, as there is limited scientific evidence supporting their effectiveness and safety.

... test Humphrey visual field analyser Biased competition theory Divided visual field paradigm Receptive field ... Look up visual field or field of vision in Wiktionary, the free dictionary. MedlinePlus Encyclopedia: Visual Field Patient Plus ... The binocular visual field is the superimposition of the two monocular fields. In the binocular field, the area left of the ... In optometry, ophthalmology, and neurology, a visual field test is used to determine whether the visual field is affected by ...
"Visual Field Testing". January 2, 2013. Siverstone, DE, Hirsch, J: Automated Visual Field Testing. Appelton-Century Croft. ... Perimetry more carefully maps and quantifies the visual field, especially at the extreme periphery of the visual field. The ... Goldmann visual field exam, or brand names such as Henson 9000 Perimeter, Humphrey Field Analyzer, Octopus Perimeter, Oculus ... A visual field test is an eye examination that can detect dysfunction in central and peripheral vision which may be caused by ...
... at topographically defined loci in the visual field. The visual field is that portion of the external environment of the ... The visual field can be considered to be all parts of the sphere for which the observer can see a particular test stimulus. If ... The visual field in this case is all of the external environment that can project light onto the retina. Meridians correspond ... Another way of thinking of the maximum visual field is to think of all of the retina that can be reached by light from the ...
Humphrey field analyser (HFA) is a tool for measuring the human visual field that is commonly used by optometrists, orthoptists ... This assesses the retina's ability to detect a stimulus at specific points within the visual field. This is called retinal ... a formula which allows the fastest and most accurate visual field assessment to date. Results are then compared against an age- ... particularly for detecting monocular visual field. The results of the analyser identify the type of vision defect. Therefore, ...
If a visual stimulus appears in the left visual field (LVF), the visual information is initially projected to the right ... if a visual stimulus appears in the right visual field (RVF), the visual information is initially received by the left cerebral ... The Divided Visual Field Paradigm is an experimental technique that involves measuring task performance when visual stimuli are ... The divided visual field paradigm capitalizes on the lateralization of the visual system. Each cerebral hemisphere only ...
... while some birds have a complete or nearly complete 360-degree visual field. The vertical range of the visual field in humans ... angular field of view, and linear field of view. Angular field of view is typically specified in degrees, while linear field of ... The range of visual abilities is not uniform across the visual field, and by implication the FoV, and varies between species. ... Field of regard Panorama Perimetry Peripheral vision Visual perception Useful field of view 35 mm equivalent focal length Angle ...
Henson, D.B. (1993). Visual Fields. Oxford: Oxford University Press. Qayyum. "Gaze Angle". Asad Qayyum. ... It gives a wider field of view. For example, humans have a maximum horizontal field of view of approximately 190 degrees with ... where the brain ignores all or part of one eye's visual field), horror fusionis (an active avoidance of fusion by eye ... although it is possible they have some binocular visual field.[how?] Other animals that are not necessarily predators, such as ...
... causes loss of vision of the right half of the right visual field and the left half of the left visual field. This visual field ... Confrontation visual field testing is a simple and quick visual field assessing method. A confrontational field test requires ... Visual system Visual field Visual field test Eye examination AK Khurana (31 August 2015). "Neuro-ophthalmology". Comprehensive ... Visual Fields via the Visual Pathway (2nd ed.). CRC Press. p. 138. ISBN 978-1-4822-9965-6. Visual fields : examination and ...
In glaucoma visual field defects result from damage to the retinal nerve fiber layer. Field defects are seen mainly in primary ... The temporal islands lie outside of the central 24 to 30° visual field, so it may not be visible with standard central field ... central field. It is only an early non-specific visual field change, without much diagnostic value in glaucoma. Small wing- ... This manifests as a gradual loss of the visual field, starting with a loss of peripheral vision, but eventually all vision will ...
"Holly Fields (visual voices guide)". Behind The Voice Actors. Retrieved January 4, 2020. "White Knight Chronicles (2010 video ... Holly Fields is an American actress. Fields was Molly Ringwald's understudy at age 7 in Through the Looking Glass. After ... Fields sings with bands and does vocal work on albums, including three of her own. She was produced by Robbie Nevil and Joey ... Fields, then age 13, was booked for the CBS pilot for CBS Summer Playhouse: Fort Figueroa (1988) and starred alongside Charles ...
Lindeberg, Tony (2013). "Invariance of visual operations at the level of receptive fields". PLOS ONE. 8 (7): e66990. arXiv: ... Lindeberg, Tony (2021). "Normative theory of visual receptive fields". Heliyon. 7 (1): e05897. Bibcode:2021Heliy...705897L. doi ... Lindeberg, Tony (2013). "A computational theory of visual receptive fields". Biological Cybernetics. 107 (6): 589-635. doi: ... The generalized scale-space theory leads to predictions about receptive field profiles in good qualitative agreement with ...
Lindeberg, T. (2013a). "Invariance of visual operations at the level of receptive fields". PLOS ONE. 8 (7): e66990:1-33. arXiv: ... Lindeberg, T. (2021). "Normative theory of visual receptive fields". Heliyon. 7 (1): e05897. doi:10.1016/j.heliyon.2021.e05897 ... Ravela, S. (2004). "Shaping receptive fields for affine invariance". Proceedings of the 2004 IEEE Computer Society Conference ...
They also have an increased binocular vision and depth of visual field as a result of the cephalofoil. The shape of the head ... McComb, D. M.; Tricas, T. C.; Kajiura, S. M. (2009). "Enhanced visual fields in hammerhead sharks". Journal of Experimental ... The pores on the shark's head lead to sensory tubes, which detect electric fields generated by other living creatures. By ...
Weltman, G.; Christianson, R. A.; Egstrom, G. H. (October 1965). "Visual fields of the scuba diver". Human Factors. 7 (5): 423- ... and this is affected by the field of vision. A narrow field of vision caused by a small viewport in a helmet results in greatly ... The visual acuity of the air-optimised eye is severely adversely affected by the difference in refractive index between air and ... A wavelength of 532 nm (green) aligns well with the peak of the human visual perception spectrum, but other wavelengths may be ...
doi:10.1111/j.1463-6395.2011.00547.x. McComb, D.M.; Tricas, T.C.; Kajiura, S.M. (2009). "Enhanced visual fields in hammerhead ... The placement of the eyes at the ends of the cephalofoil provides a binocular field of view of 48°, the most of any hammerhead ... Finally, the cephalofoil may increase the shark's ability to detect the electric fields and movements of its prey, by providing ...
Weltman, G.; Christianson, R. A.; Egstrom, G. H. (October 1965). "Visual fields of the scuba diver". Human Factors. 7 (5): 423- ... A mask is considered to fit well when it seals comfortably and effectively all round the skirt, and provides a good field of ... Double-dome masks allow a wider field of view and avoid the refraction error in perceived distance and size of objects. ...
Raptors may have to pursue mobile prey in the lower part of their visual field, and therefore do not have the lower field ... Unlike the mammalian eye, it is not spherical, and the flatter shape enables more of its visual field to be in focus. A circle ... The cost of this adaptation is that they have myopia in the lower part of their visual field. Birds with relatively large eyes ... Martin G. R. (2007). "Visual fields and their functions in birds". Journal of Ornithology. 148: 547-562. doi:10.1007/s10336-007 ...
Lindeberg, Tony (July 19, 2013). "Invariance of visual operations at the level of receptive fields". PLOS ONE. 8 (7): e66990. ... "A computational theory of visual receptive fields". Biological Cybernetics. 107 (6): 589-635. doi:10.1007/s00422-013-0569-z. ... The SIFT descriptor is based on image measurements in terms of receptive fields over which local scale invariant reference ... These features share similar properties with neurons in the primary visual cortex that encode basic forms, color, and movement ...
Martinez LM, Alonso JM (2003). "Complex receptive fields in primary visual cortex". Neuroscientist. 9 (5): 317-31. doi:10.1177/ ... In the study of visual perception, sinusoidal gratings are frequently used to probe the capabilities of the visual system, such ... a sine-wave grating of a particular frequency is presented at a particular angle in a particular location in the visual field ... The spatial-frequency theory refers to the theory that the visual cortex operates on a code of spatial frequency, not on the ...
Visual field defects can occur. In late cases cystoid macular edema sometimes develops which can further lead to macular ... Visual acuity ranges from 20/20 to 20/400. The prognosis is excellent except in case of complications of choroidal rupture, ... "Visual and anatomic outcomes of golf ball-related ocular injuries". Eye. 28 (3): 312-317. doi:10.1038/eye.2013.283. ISSN 0950- ...
"Visual arts dip into theatre for Theatrical Fields". TODAYonline. Retrieved 2018-01-01. migration (2014-05-20). "What Gillman ... a visual arts precinct in Singapore. Set up in 2013, the centre is currently headed by Founding Director Ute Meta Bauer, who is ... Pavilion of the 56th Venice Biennale by the MIT List Visual Arts Center and co-curated by Paul C. Ha, Director of the MIT List ... Theatrical Fields (curated by Ute Meta Bauer with Anca Rujoiu, first presented and commissioned by the Bildmuseet, Umea) 2014: ...
Martin, G.R.; Katzir, G. (1994). "Visual Fields and Eye Movements in Herons (Ardeidae)". Brain, Behavior and Evolution. 44 (2 ... Helm Field Guides. ISBN 0-7136-3973-3. Marchant, S.; Higgins, P.J. (1990). Handbook of Australian, New Zealand and Antarctic ... Although the cattle egret sometimes feeds in shallow water, unlike most herons, it is typically found in fields and dry grassy ... ISBN 84-87334-09-1. Crosby, G. (1972). "Spread of the Cattle Egret in the Western Hemisphere" (PDF). Journal of Field ...
Biography portal Visual arts portal "Ailene Fields - Biography". Rogallery - Ailene Fields, American. Retrieved 19 May 2014. " ... Ailene Fields Sculptures at CFM Gallery Six Summit Gallery Artists Ailene Fields - Broadhurst Gallery Ailene Fields' Plea for ... David Fields with whom she has two sons, Marc and Adam. Fields' first one-person exhibition was in 1987 at the Lavaggi Gallery ... "Ailene Fields Shows Sculpture by the Sea Shore." Manhattan Arts, NYC, June - August 1991. Wagner, J.L. "Ailene Fields a ...
doi:10.1111/j.1474-919X.1995.tb03271.x. Martin, Graham; Coetzee, Hendri C. (2003). "Visual fields in hornbills: precision- ... the bill intrudes on their visual field. This allows them to see their own bill tip and aids in precision handling of food ... Zimmerman, Dale A., Turner, Donald A., & Pearson, David J. (1999): Birds of Kenya and Northern Tanzania (Field Guide Edition). ...
... intraocular pressure and threshold visual fields. For those with visual field defects optical coherence tomography has been ... They may become apparent with an ophthalmoscope and some visual field loss at the end of adolescence. ODD can compress and ... Both the severity of optic disc drusen and the degree of intraocular pressure elevation have been associated with visual field ... May 2006). "[Optic nerve drusen and deep visual fields defects]". Arch Soc Esp Oftalmol (in Spanish). 81 (5): 269-73. PMID ...
ISBN 0-643-09133-5. Martin, G.R.; Katzir, G. (1994). "Visual Fields and Eye Movements in Herons (Ardeidae)". Brain, Behavior ... Helm Field Guides. ISBN 0-7136-3973-3. Marchant, S.; Higgins, P.J. (1990). Handbook of Australian, New Zealand and Antarctic ... Although the cattle egret sometimes feeds in shallow water, unlike most herons it is typically found in fields and dry grassy ... Crosby, G. (1972). "Spread of the Cattle Egret in the Western Hemisphere" (PDF). Journal of Field Ornithology. 43 (3): 205-212 ...
Her fields are visual perception and computer vision. She co-invented the Marr-Hildreth algorithm along with David Marr. She ... Her thesis, "The Measurement of Visual Motion", won an Honorable Mention from the Association for Computing Machinery. She is a ...
They offer a good visual field. Light weight plastic hoses provide oxygen to the helmet and remove exhaled gas to the outside ... Arthur Bulbulian, in the field of facial prosthetics, in 1941.[citation needed] Many designs of aviator's oxygen masks contain ...
... director of visual and miniature effects; Roy Field, optical visual effects supervisor; and David Lane, flying and second unit ... The visual effects unit, as well as several of the production staff, were Salkind stalwarts from the Superman films: Derek ...
Visual perception Field dependence Corbett, J.; Enns, J. (2006). "Observer pitch and roll influence: The rod and frame illusion ... These findings suggest that the rod and frame illusion is processed in a type of hierarchy, where visual input is at the top, ... Past research has found that one reason people experience the rod and frame illusion is due to visual-vestibular interactions. ... Lipshits, M.; Bengoetxea, A.; Cheron, G.; McIntyre, J. (2005). "Two reference frames for visual perception in two gravity ...
... is intense where the distractor and the target are in the same visual field than when they are in separate visual fields ... Chakravarthi R, Cavanagh P (June 2009). "Bilateral field advantage in visual crowding". Vision Research. 49 (13): 1638-46. doi: ... Visual crowding is the inability to view a target stimulus distinctly when presented in a clutter. Crowding impairs the ability ... Crowding is stronger in the upper field of the four quadrants than the lower ones. A recent study tells us that crowding ...
... may cause visual field defects. Topiramate may decrease effectiveness of oestrogen-containing oral contraceptives. ... Drugboxes which contain changes to verified fields, Drugboxes which contain changes to watched fields, All articles with ... Discontinuation of topiramate may halt the progression of the ocular damage and may reverse the visual impairment. Preliminary ... Visual disturbance Vertigo Tinnitus Ear pain Dyspnoea Epistaxis Nasal congestion Rhinorrhoea Vomiting Constipation Abdominal ...
Visual field test Humphrey visual field analyser Biased competition theory Divided visual field paradigm Receptive field ... Look up visual field or field of vision in Wiktionary, the free dictionary. MedlinePlus Encyclopedia: Visual Field Patient Plus ... The binocular visual field is the superimposition of the two monocular fields. In the binocular field, the area left of the ... In optometry, ophthalmology, and neurology, a visual field test is used to determine whether the visual field is affected by ...
The visual field refers to the total area in which objects can be seen in the side (peripheral) vision as you focus your eyes ... Confrontation visual field exam. This is a quick and basic check of the visual field. The health care provider sits directly in ... Perimetry; Tangent screen exam; Automated perimetry exam; Goldmann visual field exam; Humphrey visual field exam ... The visual field refers to the total area in which objects can be seen in the side (peripheral) vision as you focus your eyes ...
3201 Visual Field Analyzer For Sale Auction. Search and Browse hundreds of Medical Equipment Auctions on ... HAAG STREIT Octopus 600 Pro Only 6 months old Visual Field Analyzer. ... Protek RF Field Analyzer 3201 Information Auction Date: Inspection. In person or video inspection is available. Please contact ...
... , Visual Field Defect, Hemianopia, Hemianopsia, Homonymous Hemianopia, Bitemporal Hemianopia, Binasal ... Visual Field Deficit. Visual Field Deficit Aka: Visual Field Deficit, Visual Field Defect, Hemianopia, Hemianopsia, Homonymous ... Visual Field Defect with same half of Visual Field loss from each eye (left or right Visual Field) ... Objects in the Visual Field are projected onto each eyes Retina as a mirror image. *Upper right Visual Field localizes to the ...
... of subjects in whom definitive field loss did not develop on manual perimetry during the study had abnormal automated fields at ... Those with field loss on manual perimetry were more likely to have had an abnormal automated field 1 year before conversion ... Automated perimetry detects visual field loss before manual Goldmann perimetry Ophthalmology. 1995 Jan;102(1):21-6. doi: ... Subjects with field loss on manual perimetry were age-matched post hoc to subjects who did not have field loss. The automated ...
New or worsening visual field defects may indicate signs of tumor progression in glioblastoma multiforme and should prompt ... Visual field changes as an early indicator of glioblastoma multiforme progression: Two cases of functional vision changes ... Xie, K., Liu, C. Y., Hasso, A. N., & Crow, R. W. (2015). Visual field changes as an early indicator of glioblastoma multiforme ... We identify two cases where Humphrey visual field testing predated magnetic resonance imaging and positron emission tomography ...
... Epilepsia. 2013 Nov;54(11):2019. doi: 10.1111/epi. ...
... allows you to add checkout pages easily on you ... You can add custom input/output fields on ... checkout pages. This PrestaShop Additional Fields extension supports text fields ... FME Presents PrestaShop custom fields module, ( allows you to add ...
Visual Arts. The Associate in Fine Arts degree program will prepare you to transfer to a four-year college or university and ... Audio Visual and Sound Engineering (Non-Credit). At Central Piedmont, you can learn sound engineering and master editing ... Communication, English, Journalism, Visual and Performing Arts. Do you want to become an artist, actor, or dancer? Are you ... Learn more about this career field, explore related careers and salaries, and take a Career Assessment - visit Career Coach. ...
The visual field refers to the total area in which objects can be seen in the side (peripheral) vision as you focus your eyes ... Confrontation visual field exam. This is a quick and basic check of the visual field. The health care provider sits directly in ... Perimetry; Tangent screen exam; Automated perimetry exam; Goldmann visual field exam; Humphrey visual field exam ... The visual field refers to the total area in which objects can be seen in the side (peripheral) vision as you focus your eyes ...
Diagnose This: Which of these 4 visual fields is the most reliable?. ...
The commodification of the visual field requires observers that can rapidly consume visual information. The downside of this is ... The visual field becomes a commodity that has real estate value. By creating the tension between meditative state and ... Hyper-commoditized vision- monetized vision that meditates on the omnipresent advertisement targeted all over our visual field. ... the third machine contemplates on how augmenting the visual field with new technologies affects our relationship to the world ...
Our requirements are stated in our rapid response terms and conditions and must be read. These include ensuring that: i) you do not include any illustrative content including tables and graphs, ii) you do not include any information that includes specifics about any patients,iii) you do not include any original data, unless it has already been published in a peer reviewed journal and you have included a reference, iv) your response is lawful, not defamatory, original and accurate, v) you declare any competing interests, vi) you understand that your name and other personal details set out in our rapid response terms and conditions will be published with any responses we publish and vii) you understand that once a response is published, we may continue to publish your response and/or edit or remove it in the future ...
Defence of doctoral thesis in the field of Visual Communication Design, MA Laura Valojärvi. Public defences ... Defence of doctoral thesis in the field of Visual Communication Design, MA Laura Valojärvi ... The thesis concludes by providing two visual models that have emerged from the studies presented in the thesis. The first - the ...
... and if optimal correction normalized the visual field. The study included 100 patien... ... The aim of study was to establish which level of myopic refractive error influences visual field defects in automated static ... Visual field indices (MD, MS, LV, RF) were completely normalized.. Ključne riječi. myopia, anisometropia, automated static ... quantitative visual field defects, when tested by static automated perimetry. Even in optimally corrected myopics, with myopia ...
Many visual field maps exist, suggesting that every map contains a unique representation of the visual field. This notion ... These receptive fields are organized into visual field maps, where neighboring neurons process neighboring parts of the visual ... the receptive field is a property of individual neurons and summarizes the region of the visual field where visual stimulation ... Visual receptive fields have dynamic properties that may change with the conditions of visual stimulation or with the state of ...
Is there a way to stop this field ... ... I have used the following code to add a new field to a database ... I have used the following code to add a new field to a database. Is there a way to stop this field having a Null value but ... Create and append new Field objects tbl.Fields.Append tbl.CreateField("Extra", dbText, 20). ... u cant use both stop entering null value into a field and allow it to keep empty together.instead of u can restrict the user ...
What does the receptive field of a visual cell refer to quizlet?. The receptive field of a visual cell refers to the. Retinal ... For any cell in the visual system, from the retina to the brain, there is an area out in the visual field that will produce a ... What is a receptive field in the visual system?. RECEPTIVE FIELDS, FROM THE RETINA TO THE CORTEX. Each of the neurons in the ... What is an example of receptive field?. Why receptive field is important?. The concept of the receptive field is central to ...
... aided by state-of-the-art audio-visual technology. ... An oil field services company, employing personnel working ... Barco partners with leading tech suppliers to deliver bespoke audio-visual solution for oil field services company.. ... Barco partners with leading tech suppliers to deliver bespoke audio-visual solution for oil field services company. ... An oil field services company, employing personnel working across 120 countries, selected Barco to assist with the development ...
Two-Year Randomized, Placebo-Controlled Study of Black Currant Anthocyanins on Visual Field in Glaucoma Subject Area: ... Ogawa T, Ogawa A, So K: Target intraocular pressure and risk factors for progression of visual field loss in primary open-angle ... Hart WM, Becker B: The onset and evolution of glaucomatous visual field defect. Ophthalmology 1982;89:268-279. ... and Humphrey visual field mean deviation (MD) were measured during the 24-month period. Results: As a main outcome measurement ...
After taking school field trips use a visual field trip follow-up form as a way for students to review all of the information ... A Visual Field Trip Follow-up form is a one-page pictorial summary of things the students might have seen on their field trip. ... Try a Visual Field Trip Follow-up form to determine how your students benefitted from the experience. Students can circle ... Home , Watson Life Resources , Life Skills , Visual Field Trip Follow Up Form ...
PS3.16 , DCMR Context Groups (Normative) , Visual Field Static Perimetry Fixation Strategy CID 4253 Visual Field Static ... CID 4252 Visual Field Static Perimetry Screening Test Mode Home CID 4254 Visual Field Static Perimetry Test Analysis Result. ...
The Department also distributes audio/visual gear for institutional use contained in the building. To report problems, call the ... Elevate your small business with industrial audio visual solutions that enhance the way you converse, present, talk and ... audio/visual telephone quantity at extension (from outdoors the building name ). ...
Emily Brandt, MD is a board-certified Developmental-Behavioral Pediatrician at Anna Shaw Childrens Institute in Dalton, GA. Dr. Brandt specializes in attention disorders, autism spectrum disorders, behavioral and developmental challenges, and more. Dr. Brandt has cared for children with developmental delays and has assisted with educating medical students, pediatrics residents, and child psychiatry residents during her fellowship at the University of Iowa and as a member of the faculty at the University of Tennessee College of Medicine in Chattanooga. Call 706.226.8900 for more information.. ...
Writing value to datetime field in SQL database in dd/mm/yyyy format. Visual Basic .NET Forums on Bytes. ... home , topics , visual basic .net , questions , writing value to datetime field in sql database in dd/mm/yyyy format ... this field (and others) need to be written back to a SQL database.. The date field will be input in the format of the ... this field (and others) need to be written back to a SQL database.. The date field will be input in the format of the ...
Ethics in the Field: Research Practice in Audio-Visual Studies Authors. * Maximilian Krug Universität Duisburg-Essen ... Krug, M., & Heuser, S. (2018). Ethics in the Field: Research Practice in Audio-Visual Studies. Forum Qualitative ... research ethics, conversation analysis, audio-visual data, multimodality, eye tracking Abstract. Audio-visual recording of ...
Tag Archives: visual studio gaming field. *Home / *Posts tagged "visual studio gaming field" ... In addition to software development, Microsoft has also made significant contributions to the field of gaming with its Xbox ...
Abstract:Abstract: Visual-angle has been used as the conventional unit to determine the field-of-view (FOV) in traditional ... Title:Understanding the relationship between visual-angle and eye-angle for reliable determination of the field-of-view in ... the relationship between visual-angle and eye-angle for reliable determination of the field-of-view in ultra-wide field fundus ... the relationship between visual-angle and eye-angle for reliable determination of the field-of-view in ultra-wide field fundus ...
A visual checklist manifesto in a 3D interactive format makes sure steps arent missed and shows what you should be doing - ... At Heartwood, we take the checklist beyond the clipboard and provide visual cues to guide your technicians through various ...
Each patient had visual field assessment using the HFA and the MRF app in clinic. They were then given a 20 minute training ... Yu Xiang George Kong, Mingguang He, Selwyn Marc Prea, Algis J Vingrys; Self Directed Home Monitoring of Visual Field with ... There is a tendency for greater test variability in patients with worse visual field defect as indicated by MD (R=0.52). ... Conclusions : This study finds good compliance and test-retest reliability in the short term for self directed visual field ...
  • Glaucoma causes peripheral field defects. (
  • The main classification of visual field defects is into Lesions to the eye's retina (heteronymous field defects in Glaucoma and AMD) Lesions of the optic nerve (heteronymous field defects) Lesions in the chiasm (e.g. (
  • Visual field testing in glaucoma. (
  • Abnormal results detected on the Humphrey Field Analyzer were defined using the glaucoma hemifield test, mean defect, and corrected-pattern standard deviation. (
  • Seventy-five percent of converters had abnormal results of the glaucoma hemifield test 1 year before field loss on manual perimetry, whereas 22% of controls had abnormal results of the glaucoma hemifield test (odds ratio, 13.4). (
  • The odds ratio of field loss developing on manual perimetry within 12 months was 3.3 for those with borderline results of the glaucoma hemifield test relative to the control subjects. (
  • Future longer term clinical trials are required to determine the ability of visual field home monitoring in detecting glaucoma progression. (
  • A visual field test can detect vision loss caused by a possible brain tumour, stroke or eye diseases such as glaucoma or diabetic retinopathy . (
  • There are certain patterns of localised visual field defects that are typical of different eye diseases, including glaucoma. (
  • If you have a glaucoma-suspicious visual field defect, your optometrist will investigate this thoroughly. (
  • An abnormal visual field test could indicate early signs of glaucoma, but further tests will need to be done to confirm this. (
  • Visual field defects in glaucoma are caused by damage to the sensitive nerves at the back of the eye, in the layer known as the retina. (
  • People with early signs of glaucoma may just have lowered sensitivity to light in one part of their visual field. (
  • FDT perimetry tools enable doctors to assess visual field loss due to glaucoma earlier and with superior accuracy compared to other testing protocols. (
  • Visual field testing is one of the most effective diagnostic treatments in the detection of glaucoma. (
  • If you have been diagnosed with glaucoma, you will probably be recommended to have several visual field tests each year, which will help your eye doctor to monitor the progression of your condition and recommend treatments to slow it. (
  • Patients with chronic diseases, such as glaucoma, need to undergo a visual field test at least three times a year. (
  • Cite this: Virtual Reality Takes the Field in Glaucoma - Medscape - Jun 06, 2023. (
  • Glaucoma surgery decreases the rates of localized and global visual field progression. (
  • We sought to determine the efficacy of glaucoma surgery in decreasing localized and global rates of visual field (VF) progression. (
  • Macular degeneration and other diseases affecting the macula cause central field defects. (
  • To determine if automated perimetry detects visual field defects before manual Goldmann perimetry. (
  • Forty subjects who had field loss during 8 years of follow-up were compared with 145 control subjects with ocular hypertension who did not have defects. (
  • New or worsening visual field defects may indicate signs of tumor progression in glioblastoma multiforme and should prompt further investigation. (
  • The aim of study was to establish which level of myopic refractive error influences visual field defects in automated static perimetry, if these defects are typical, and if optimal correction normalized the visual field. (
  • This study confirms that optimal corrected and uncorrected myopia up to -3.25 Dsph does not produce quantitative visual field defects, when tested by static automated perimetry. (
  • Even in optimally corrected myopics, with myopia higher than -5.50 Dsph, visual field defects on gray scale can be found. (
  • It's generally only repeatable field defects that may be a cause for concern. (
  • Visual field defects can spread over time and could lead to tunnel vision , where only a small central area of vision is left. (
  • In the present study, an evaluation of the EFA with the help of blind spots of 58 healthy participants and the individual visual field defects of 23 clinical patients is provided. (
  • Conclusion Outcomes indicate that the EFA is highly reliable and precise in diagnosing individual shape and location of scotoma and capable of recording changes of visual field defects (after intervention) with unprecedented precision. (
  • The VR headset had difficulty capturing and would at times underestimate more profound defects in the visual field or miss isolated defects. (
  • Damage along the optic pathway causes a variety of visual field defects. (
  • With retrochiasmal lesions, visual field defects are on the same side (homonymous) and tend to become more symmetric (congruous) with more posterior lesions, as shown with the occipital lesion in #4. (
  • The visual field is measured by perimetry. (
  • Subjects with ocular hypertension without field loss on detailed manual perimetry were followed prospectively with annual automated and manual perimetry. (
  • Subjects with field loss on manual perimetry were age-matched post hoc to subjects who did not have field loss. (
  • The automated fields 1 year before the development of field loss on manual perimetry were compared between the two groups. (
  • Those with field loss on manual perimetry were more likely to have had an abnormal automated field 1 year before conversion than those who did not convert. (
  • However, 22% of subjects in whom definitive field loss did not develop on manual perimetry during the study had abnormal automated fields at one visit and 15% had abnormal automated fields on two consecutive visits. (
  • 2013). 'Automated Static Perimetry: The Influence of Myopic Anisometropia on Evaluation of Visual Field', Collegium antropologicum , 37 Supplement 1(1), str. (
  • Perić S, Cerovski B, Perić P, Škegro I, Tiljak H. Automated Static Perimetry: The Influence of Myopic Anisometropia on Evaluation of Visual Field. (
  • With the help of the EFA, optical coherence tomography, Goldmann perimetry and a Humphrey field analyser, these natural and acquired scotomas were diagnosed and the results were compared accordingly. (
  • Also sometimes known as perimetry testing, Visual field testing is a method to measure the entire scope of vision of an individual, including their peripheral/side vision. (
  • Perimetry (visual field test) is one of the basic ophthalmic and neurological examinations. (
  • Computerized perimetry makes it possible to accurately determine and analyze the so-called retinal sensitivity threshold, and map the patent's central and peripheral visual field. (
  • i2Eye Diagnostics Limited plans to create a visual field analyser using the latest in Saccadic Vector Optokinetic Perimetry (SVOP) technology. (
  • What is Saccadic Vector Optokinetic Perimetry (SVOP) technology and how will it benefit the visual field analyser? (
  • During active treatment, serial eye exams including assessment of the optic nerve appearance and static perimetry are essential to follow the visual function of these patients. (
  • Virtual-reality (VR) visual field monitoring could enable a pivot away from traditional in-office automated perimetry. (
  • Whether attempting to duplicate traditional visual field testing in VR with a consistent fixation point and clicker or by utilizing a proprietary software package to map out a dynamic visual field, VR visual field testing is beginning to approach parity with the traditional perimetry methods. (
  • In one head-to-head study , VR visual field and traditional perimetry were shown to have high overall field correlation with consistent mean deviations and comparable reliability indices between the two methods. (
  • Exclusion criteria were: inability to understand English instructions given by the iPad, visual acuity worse than 6/12, intraocular surgery in past 6 months. (
  • Every eye exam includes an assessment of visual acuity. (
  • Visual acuity and field of vision of urban and rural Egyptians. (
  • 1969). Visual acuity and field of vision of urban and rural Egyptians. (
  • Severe visual impairment" is defined as a presenting visual acuity of between less than 6/60 and 3/60 and "moderate visual impairment" as a presenting visual acuity of less than 6/18 to 6/60. (
  • Patients with ocular trauma, bandages, pre-existing blindness or other 2 = Forced deviation, or total gaze paresis not overcome by the disorder of visual acuity or fields should be tested with reflexive oculocephalic maneuver. (
  • Commonly used perimeters are the automated Humphrey Field Analyzer, Optopol Perimeters, Octopus, the Heidelberg Edge Perimeter, or the Oculus. (
  • In the clinical setting with technician guidance, the iPad based app (Melbourne Rapid Fields, MRF) is able to produce perimetric results with high correlations with Humphrey Field Analyzer (HFA) outcomes. (
  • To date, a few studies have sought to prove noninferiority to conventional Humphrey Field Analyzer testing. (
  • This symposium will highlight current concepts of the organization of visual cortex and their relation to perception and plasticity. (
  • We will describe data-analysis techniques to reconstruct receptive field properties of neural populations, and extend them to visual field maps and clusters within human and macaque visual cortex. (
  • The link between visual cortex' organization, perception and plasticity is a fundamental part of vision science. (
  • We describe a method that reconstructs population receptive field (pRF) properties in human visual cortex using fMRI. (
  • Receptive fields of cells in the visual cortex are larger and have more-complex stimulus requirements than retinal ganglion cells or lateral geniculate nucleus cells. (
  • Objective Several studies report evidence for training-related neuroplasticity in the visual cortex, while other studies suggest that improvements simply reflect inadequate eye fixation control during perimetric prediagnostics and postdiagnostics. (
  • Another method is for the practitioner to hold up one, two, or five fingers in the four quadrants and center of a patient's visual field (with the other eye covered). (
  • It aims at detecting and locating blind spots in the patient's visual field. (
  • If left untreated, chronic papilledema may lead to secondary progressive optic atrophy, visual field loss, and ultimately blindness. (
  • The causes and magnitude of blindness and visual impairment need to be determined before appropriate strategies can be developed and international alliances for the prevention of blindness alliances established. (
  • This initiative has promoted WHO's strategy for the prevention of avoidable blindness and visual impairment, which is based on disease control, human resource development, and infrastructure and technology. (
  • Continued systematic collection of epidemiological data on blindness and visual impairment enabled WHO to publish more detailed statistics in 2004 and 2006. (
  • If there is unilateral ______ blindness or enucleation, visual fields in the remaining eye are scored. (
  • Global indices used to approximate the rate of visual field loss over time. (
  • The indices represent the entire visual field as a single percentage of normal. (
  • These receptive fields are organized into visual field maps, where neighboring neurons process neighboring parts of the visual field. (
  • Next, we extend conventional stimulus-referred notions of the receptive field to neural-referred properties, i.e. cortico-cortical receptive fields that capture the information flow between visual field maps. (
  • Receptive fields have been identified for neurons of the auditory system, the somatosensory system, and the visual system. (
  • There are two primary types of ganglion cell receptive fields: ON center/OFF surround cell: Flashing small bright spot in the center subregion increases the cell's response. (
  • What is the difference between retinal ganglion and receptive fields? (
  • Receptive fields are similar to those of ganglion cells, with an antagonistic center-surround system and cells that are either on- or off center. (
  • Lesions of the visual pathway cause characteristic forms of visual disturbances, including homonymous hemianopsia, quadrantanopsia, and scotomata. (
  • Precise and reliable visual field diagnostics is of crucial importance when diagnosing progression in eye diseases or evaluating rehabilitation after brain lesions. (
  • Your responses help determine if you have a defect in your visual field. (
  • There is a tendency for greater test variability in patients with worse visual field defect as indicated by MD (R=0.52). (
  • A diffuse visual field defect happens when the overall sensitivity of the eyes is lower than average. (
  • A localised field defect happens when a particular area of the visual field has reduced sensitivity, so it's harder for that person to detect the lights appearing in that location. (
  • At the smallest scale, the receptive field is a property of individual neurons and summarizes the region of the visual field where visual stimulation elicits a response. (
  • Each of the neurons in the various layers of the retina "covers" an area in your field of vision. (
  • The receptive field encompasses the sensory receptors that feed into sensory neurons and thus includes specific receptors on a neuron as well as collectives of receptors that are capable of activating a neuron via synaptic connections. (
  • We also demonstrate techniques to reveal extra-classical receptive field interactions similar to those seen in classical psychophysical "surround suppression" in both S-cone and achromatic pathways. (
  • In optometry, ophthalmology, and neurology, a visual field test is used to determine whether the visual field is affected by diseases that cause local scotoma or a more extensive loss of vision or a reduction in sensitivity (increase in threshold). (
  • Visual field loss may occur due to many disease or disorders of the eye, optic nerve, or brain. (
  • This eye exam will show whether you have a loss of vision anywhere in your visual field. (
  • Visual field tests are specifically used to detect areas of vision loss (blind spots). (
  • Your optometrist uses the visual plot field to compare your visual field test to others from people of a similar age, as well as looking for any loss of sensitivity across the visual field. (
  • This information will be used to look for any loss of sensitivity across the visual field. (
  • The earlier visual field problems are detected the better, as treatment can slow or stop the progression of sight loss. (
  • OBJECTIVE: To assess the prevalence of pathogenic CYP1B1 sequence variants in an Australian cohort of patients with JOAG and severe visual field loss. (
  • We defined JOAG as diagnosis before age 40 years and advanced JOAG as visual field loss in 2 of the 4 central fixation squares on a reliable visual field test result. (
  • CONCLUSIONS AND RELEVANCE: Patients with advanced JOAG based on visual field loss had enrichment of CYP1B1 pathogenic variants and a more severe phenotype compared with unaffected controls and patients with nonadvanced JOAG. (
  • The Humphrey FDT Perimeter uses Welch Allyn Frequency Doubling Technology to provide a clinically verified, fast and affordable means of detecting early visual field loss. (
  • The results are presented in the form of a graphic map that shows visual field loss, if there is any. (
  • It is also used to measure the visual fields of young children who have had strokes, who have visual field loss due to prematurity (periventricular leucomalacia), and who have had brain damage due to infection. (
  • Corticosteroids should only be considered on a very short-term basis in patients who present with marked loss of visual function. (
  • Mobile or home-based testing could facilitate closer monitoring of visual field loss and alert physicians to patients who need further evaluation. (
  • Visual fields (upper and lower quadrants) are tested by 0 = No visual loss confrontation, using finger counting or visual threat as appropriate. (
  • Types of field loss may include bitemporal loss, concentric constriction, and enlarged blind spots. (
  • However, pregnant women with symptomatic visual field loss warrant further investigations. (
  • However, it can also be used to detect central or peripheral retinal diseases, eyelid conditions such as drooping, optic nerve damage and conditions that affect the visual pathways from the optic nerve to the area of the brain where this information is processed into vision. (
  • This notion relates the visual field maps to the idea of functional specialization, i.e. separate cortical regions are involved in different processes. (
  • Indeed most perceptual functions are associated with multiple visual field maps and even multiple cortical regions. (
  • PRF sizes increase between visual areas and with eccentricity, but when expressed in V1 cortical surface area (i.e., cortico-cortical pRFs), they are constant across eccentricity in V2 and V3. (
  • Systemic blood pressure, pulse rates, intraocular pressure (IOP), ocular blood circulation by laser-speckle flowgraphy, and Humphrey visual field mean deviation (MD) were measured during the 24-month period. (
  • 7. The relationship between control of intraocular pressure and visual field deterioration. (
  • We identify two cases where Humphrey visual field testing predated magnetic resonance imaging and positron emission tomography findings of tumor progression by months in glioblastoma multiforme. (
  • We spoke to the inventor of the i2Eye visual field analyser, Professor Brian Fleck, to get the lowdown on the new device. (
  • Could you please explain how the visual field analyser works? (
  • What will be the advantages of the visual field analyser? (
  • How will the new visual field analyser affect the future of monitoring eye disease and brain tumours in children? (
  • Investigative Ophthalmology & Visual Science July 2019, Vol.60, 2486. (
  • 2 To prevent and reduce disease, disability and premature death from chronic noncommunicable conditions, mental disorders, violence and injuries and visual impairment. (
  • Recently emerging usage of eye-angle as the unit in wide field fundus photography creates confusions about FOV interpretation in instrumentation design and clinical application. (
  • It is an effective agent for lowering ICP, and it was shown to improve the visual function of patients with IIH in a randomized, controlled, clinical trial. (
  • These asymptomatic visual field changes were shown to be completely reversible postpartum. (
  • Receptive field, region in the sensory periphery within which stimuli can influence the electrical activity of sensory cells. (
  • The visual field refers to the total area in which objects can be seen in the side (peripheral) vision as you focus your eyes on a central point. (
  • A visual field test is a simple test which measures your peripheral vision and all-around vision. (
  • In many instances, most of the visual field of a predator does not fall within a high-resolution area of the retina and so, when an undetected prey moves, that motion will often be in peripheral vision. (
  • This involves points of light that are fixed in size and intensity and are presented along the patient's peripheral vision, before being gradually moved inwards to determine their field of vision. (
  • If you would like more information about visual field testing, or if you have concerns about your peripheral vision, please don't hesitate to schedule an appointment with our experienced and knowledgeable eyecare team today. (
  • The G2 and NEO can be equipped with an automated assessment of a patient's visual sensitivity to contrast. (
  • Abstract: Visual-angle has been used as the conventional unit to determine the field-of-view (FOV) in traditional fundus photography. (
  • Generate and evaluate complex ideas and concepts at an abstract level using cognitive, technical and creative skills and relate them to their own creative works and to recent developments in the field. (
  • In addition, young children with a range of developmental abnormalities may turn out to have visual field problems that have not previously been detected. (
  • The receptive field of a visual cell refers to the. (
  • Saccadic Vector" refers to the measurement of eye movement direction measured by the eye tracker during testing of a point in the visual field. (
  • There are many variants of this type of exam (e.g., wiggling fingers in the visual periphery on the cardinal axes). (
  • The customer wanted the space to provide intimate meeting areas where colleagues could break away to run brainstorming sessions and collaborate on team projects, while delivering a larger seated area where audiences could interact with visual content and on-screen presentations. (
  • The video wall was able to fulfil the customer's criteria as it presents a uniformity across its bezel-less panels resulting in almost imperceptible gaps between each tile to deliver a greater flexibility and clarity of visual content. (
  • As a result, each of our VF2000 devices perform all the industry standard, reliable visual field testing while being more accessible and convenient than the old standard HFA, plus, a growing number of advanced vision tests can be added to 2 of the 3 models, helping you gather more information about your patients' vision more efficiently than ever before. (
  • Test duration is comparable to established instruments and due to the high customisability of the EFA, assessment duration can be shortened by adapting the diagnostic procedure to the patients' individual visual field characteristics. (
  • Visual field testing is non-invasive, painless and doesn't require patients to have their eyes dilated. (
  • Why is it so hard to test visual fields in paediatric patients, vulnerable adult and elderly patients? (
  • It might even be possible for patients to perform preappointment visual field tests at home, allowing their physicians to review the results in advance, streamlining patient visits. (
  • We look forward to adding VR visual field testing to diagnostic offerings for our patients and anticipate that as more practices adopt this technology, the data collected will lead to the continued improvement and increased reliability of the results. (
  • Un échantillon choisi à dessein de 50 patients souffrant de glaucome, âgés de 12 à 18 ans, consultant un centre de soins externes en ophtalmologie au Caire (Égypte) a bénéficié d'un programme éducatif sur cette maladie, visant à corriger leurs idées fausses et leurs attentes, et comportant des démonstrations et des formations de perfectionnement sur les soins oculaires. (
  • This article describes the test that measures your visual field. (
  • This study finds good compliance and test-retest reliability in the short term for self directed visual field testing at home. (
  • What is a visual field test? (
  • A visual field test is a way to measure what you can see above, below and all-around. (
  • The visual field machine will complete an analysis of the responses given during the test and collate these results in a visual plot field. (
  • Why do I need a visual field test? (
  • You can find out more about visual field test results interpretation here, including what an abnormal visual field test means. (
  • What can a visual field test detect? (
  • A normal visual field test means that someone can see well through the centre and around the edges of their vision. (
  • A normal visual field test result measures 90 degrees temporally, 50 degrees superiorly and nasally, and 60 degrees inferiorly. (
  • You can find out more about visual field test results here. (
  • What does an abnormal field visual test mean? (
  • It's important to note that many people who are not familiar with a visual field test, or perhaps did not understand the test fully, can find it difficult on their first attempt. (
  • All 3 devices come equipped with more than 20, threshold, static and kinetic visual field protocols plus neuro testing, ptosis testing, and the Esterman binocular test. (
  • Another notable benefit is that by utilizing dynamic visual field mapping with eye tracking and head positioning information , test duration could be shortened while improving patient engagement and attentiveness. (
  • That's why your optometrist will consider your visual field results along with the results from other tests carried out during your eye exam. (
  • Currently, about 314 million people worldwide live with visual impairment due to either eye diseases or uncorrected refractive errors. (
  • Learn more about this career field, explore related careers and salaries, and take a Career Assessment - visit Career Coach . (
  • Each patient had visual field assessment using the HFA and the MRF app in clinic. (
  • Visual field maps are organized in clusters that share a similar eccentricity organization. (
  • The normal (monocular) human visual field extends to approximately 60 degrees nasally (toward the nose, or inward) from the vertical meridian in each eye, to 107 degrees temporally (away from the nose, or outwards) from the vertical meridian, and approximately 70 degrees above and 80 below the horizontal meridian. (
  • Hyper-commoditized vision - monetized vision that meditates on the omnipresent advertisement targeted all over our visual field. (
  • Furthermore, we will consider how these neural properties change with the state of chronic visual deprivation due to damage to the visual system, and in subjects with severely altered visual input due to prism-adaptation. (
  • The aim ers after reviewing the relevant visual field due to damage to the optic of the current study was to evaluate the literature. (
  • These images are a random sampling from a Bing search on the term "Visual Field Deficit. (
  • Select up to three search categories and corresponding keywords using the fields to the right. (
  • Develop practice-led methodologies through investigation, analysis and synthesis of complex information to plan and execute a substantial, creative field-generated research project. (
  • If the patient is able to report the number of fingers properly as compared with the visual field of the practitioner, the normal result is recorded as "full to finger counting" (often abbreviated FTFC). (
  • This is where a machine is used to quantify how well the patient is able to detect flashing lights of varying size and brightness in different areas of their visual field, while they concentrate on a central point. (
  • Traditional visual field testing requires a high level of concentration and cooperation by the patient. (
  • If that part of the visual field is working, the patient will look at the new point (fixation saccade) and the machine will record that this has been done accurately. (