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.
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.
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)

Upon investigating -the effects of monocular visual field loss in glaucoma patients, a team of Chinese researchers found that the binocular visual field remains relatively intact as long as one eye is at normal or early stage.. This observational, cross-sectional study evaluated 250 glaucoma patients and 31 healthy patients who were assigned to groups according to the stage of monocular visual field loss they were experiencing: normal, early, moderate or severe. The researchers assessed the binocular visual fields via integrated visual field and Esterman binocular visual evaluations and compared monocular and binocular visual field parameters within and among groups. In patients with one eye at normal or early stage and the other at severe stage, the team found that the average integrated mean deviations were -1.67dB and -3.27dB, respectively, and the average Esterman scores were 99.17% and 96.08%, respectively. In patients with both eyes at moderate or severe stage, they notes that the average ...
Upon investigating -the effects of monocular visual field loss in glaucoma patients, a team of Chinese researchers found that the binocular visual field remains relatively intact as long as one eye is at normal or early stage.. This observational, cross-sectional study evaluated 250 glaucoma patients and 31 healthy patients who were assigned to groups according to the stage of monocular visual field loss they were experiencing: normal, early, moderate or severe. The researchers assessed the binocular visual fields via integrated visual field and Esterman binocular visual evaluations and compared monocular and binocular visual field parameters within and among groups. In patients with one eye at normal or early stage and the other at severe stage, the team found that the average integrated mean deviations were -1.67dB and -3.27dB, respectively, and the average Esterman scores were 99.17% and 96.08%, respectively. In patients with both eyes at moderate or severe stage, they notes that the average ...
Exercise reduces intraocular pressure (IOP) in the short term. However, it is not known whether exercise contributes to slower glaucomatous visual field defect progression. Twenty-four primary open-angle glaucoma or exfoliation glaucoma patients who were evaluated by the Humphrey Field Analyzer (HFA) 24-2 program ≥ four times in 3 years were enrolled. Patients with a history of intraocular surgery in past 3 years or other eye diseases threatening visual fields were excluded. Patients were classified into two groups whether they had exercise habits or not. Eleven patients had exercise habits. The mean ± standard error of IOP and MD slope were 14.8 ± 0.9 mmHg and +0.20 ± 0.20 dB/year in the exercise group and 13.3 ± 0.8 mmHg and −0.53 ± 0.18 dB/year in the non-exercise group (P = 0.24 and P = 0.01, respectively). Higher IOP [odds ratio (OR) = 0.44/1 mmHg increase; P = 0.02] and habitual exercise (OR = 0.04; P = 0.02) reduced the visual field defect progression risk in logistic regression analyses
Many eye and brain disorders can cause peripheral vision loss and other visual field abnormalities. Visual field tests are performed by eye care professionals to detect blind spots (scotomas) and other visual field defects, which can be an early sign of these problems.. The size and shape of a scotoma offer important clues about the presence and severity of diseases of the eye, optic nerve and visual structures in the brain. For example, optic nerve damage caused by glaucoma creates a very specific visual field defect.. Other conditions associated with blind spots and other visual field defects include diseases of the retina, optic neuropathy, brain tumors and stroke.. ...
If you have glaucoma, and some loss of visual field is present, you will be followed carefully with repeated testing to determine if the problem has been halted or if further loss is occurring. With further loss of visual field, you often will require additional treatment. The time interval between visual field tests depends on many different factors, and is best determined by your ophthalmologist. This ongoing and repeated testing is very important for the proper management of your glaucoma. In a healthy eye, the central portion of the visual field corresponds to the area of best vision. On the left, the numbers tell how bright the test lights had to be in order to be detected. Higher numbers indicate better vision. On the right, the visual field map shows the lightest areas (best vision) are in the center, with some reduction in sensitivity in the periphery, even in the normal field. The darkest area corresponds to the normal blind spot. The glaucoma eye shown here required more light than ...
Purpose : To compare healthcare utilization and visual field progression of glaucoma patients who add or switch topical therapies vs. patients managed on topical monotherapy. Methods : This was a retrospective analysis of Kaiser Permanente Southern California electronic health records between 2001 and 2011, with supplemental chart review. Records of newly-diagnosed glaucoma (ICD-9 365.xx) patients aged 18 years or older and prescribed a glaucoma agent within 90 days of diagnosis were included. Two cohorts were defined: patients treated with topical monotherapy for the study duration, and patients who switched or added drugs at any time during follow-up. Outcomes of interest included health care utilization measured by office visits, visual field testing, laser procedures, and surgery. The risk of visual field progression was assessed using multivariable Cox regression. Results : 6,014 newly diagnosed glaucoma patients were included for analyses; 1,783 remained on monotherapy and 4,231 ...
The average human visual field extends 60 degrees nasally, 90 to 100 degrees laterally and 150 degrees vertically around the central point of vision. The visual fields overlap by approximately 120 degrees, giving stereopsis (depth perception). Visual acuity is sharpest centrally, where the photoreceptors on the retina are closer together, with image resolution and colour perception being reduced in the peripheral visual field.. Visual field problems can be a sign of underlying ophthalmic or neurological disease. Because the retinal ganglion cells travel in a precise anatomical location from the retina to the lateral geniculate nucleus, and the relative positions of the axons are preserved in the optic radiations from this nucleus to the occipital cortex, it is possible to localise abnormalities based on assessment of the visual field (Figure 1).. Picture credit: © Jan Mika/Depositphotos. Model used for illustrative purposes only.. ...
The NuCoria Visual Field Analyzer (nCFA) makes objective visual field testing a clinical reality.The NuCoria VIsual Field Analyzer It combines objectivity with
Conflicting results have been obtained regarding the impact of homonymous visual field loss on driving. The driving deficits reported include inappropriate lane positioning, space judgement, inconsistent steering and increased risk of collisions (Bowers et al. 2009; Kooijman et al. 2004; Kunimatsu-Sanuki et al. 2015; Lövsund et al. 1991; McGwin et al. 2015; Ono et al. 2015; Rubin et al. 2007; Szlyk et al. 1993, 2005; Tant et al. 2002). On the other hand, further studies found little difference in performance between hemianopes and those with full fields (Schulte et al. 1999; Wood et al. 2009). Differences may be due to methodological variations, for example, whether the assessment was on-road or simulated (Wood et al. 2009). Other potential factors are sample size, inclusion criteria and time since onset/adaptation time.. Quadrantanopia is a less extensive visual field defect that affects a quarter of the visual field area. Safe driving appears to be more achievable with this defect than in ...
Purpose : To predict glaucomatous visual field (VF) worsening after at least 5 years using features of 3 baseline VFs.. Methods : In this retrospective multi-center cohort study, eyes with ≥ 5 reliable automated VFs and ≥ 5 years follow-up were selected. We also restricted the time between each follow-up VFs to be ≥ 6 months, the time between the first and third VFs to be ≤ 3 years, and glaucoma hemifield test (GHT) to be within/outside normal limits or borderline. VF features are extracted: (1) age, follow-up time, mean deviation (MD) and pattern standard deviation (PSD) of the 3rd VF, (2) GHT results, MD slope, PSD slope and intraclass correlation for the 3 baseline VFs, and (3) worsening VF locations using permutation of pointwise linear regression (PoPLR, slope,-1 dB/year and p,0.01) and the Collaborative Initial Glaucoma Treatment Study (CIGTS) score of the 3rd VF based on the 3 baselines. Worsening VFs were determined by CIGTS criteria, MD regression (minus slope, p,0.01) and PoPLR ...
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Reading is one skill in particular that visual field loss can impact on in a variety of ways, depending on the location and size of the visual field loss. For those reading English (and other languages read from left to right) it may be difficult to locate the next word on the same line if you have a right-sided visual field loss, and it can be difficult to locate the start of the next line if you have a left-sided visual field loss. When the field loss includes an area of the central field called the macular region there is often a corresponding loss of visual acuity and reading small text becomes more difficult.. The evidence for improvements in reading ability after vision rehabilitation is variable but suggests positive outcomes that depend on the specific training program, and on the specific area of the visual field loss. For those interested in therapy options for patients who have difficulty reading as a result of visual field loss you may wish to visit University College Londons ...
ii) Ophthalmological exclusion criteria: diabetic retinopathy, infections (e.g. keratitis, conjunctivitis, uveitis), severe dry eyes, miotic drug, amblyopia, squint, nystagmus, albinism, any ocular pathology, in either eye, that may interfere with the ability to obtain visual fields, disc imaging or accurate IOP readings, keratoconus, intraocular surgery (except for uncomplicated cataract surgery) performed , 3 month prior to screening, history or signs of any visual pathway affection other than glaucoma, allergies with regard to topic glaucoma medication, history or presence of macular disease and / or macular edema, ocular trauma.. - Normal subjects. (i) General exclusion criteria: mental or neurological diseases, diabetes mellitus, history of coronary heart disease, stroke, migraine, vasospasm / Raynaud`s disease; drugs indicating severe systemic diseases (e.g. anti-diabetic or anti-hypertensive medication for subjects under 70 years of age), drugs or medications influencing reaction time, ...
Exposed to large coherently moving scene can generate illusion of self-motion perception (vection) among stationary viewers. Depending on the susceptibility to visually induced motion sickness (VIMS), the vection experiences can vary. Past studies exploring the brain activity during vection did not focus on vection onset and individual differences in vection perception. This study aims to identify EEG markers that correlate with the onset and duration of individual vection perception, along with the VIMS susceptibility. We recorded pattern-reversed visual evoked potentials (VEPs) in central visual field while two types of stimuli (static vs. rotating dot pattern) were presented to the peripheral visual field. Eight subjects were recruited with sufficient training to fix their eyes in the central fixation point and press buttons to report their perception state (vection or no-vection) during the stimuli presentation. An achromatic checkerboard reversing every 500ms was used to evoke VEPs. A total ...
Much of the visual cortex is organized into visual field maps: nearby neurons have receptive fields at nearby locations in the image. Mammalian species generally have multiple visual field maps with each species having similar, but not identical, maps. The introduction of functional magnetic resonan …
One of the factors proposed to regulate the eye growth is the error signal derived from the defocus in the retina and actually, this might arise from defocus not only in the fovea but the whole visual field. Therefore, myopia could be better predicted by spatio-temporally mapping the environmental defocus over the visual field. At present, no devices are available that could provide this information. A Kinect sensor v1 camera (Microsoft Corp.) and a portable eye tracker were used for developing a system for quantifying indoor defocus error signals across the central 58° of the visual field. Dioptric differences relative to the fovea (assumed to be in focus) were recorded over the visual field and defocus maps were generated for various scenes and tasks.. © 2017 Optical Society of America under the terms of the OSA Open Access Publishing Agreement. Full Article , PDF Article ...
Suprathreshold field screeners are in common use for the detection of glaucomatous field loss. The predictive power of a positive result (PP+) depends on the sensitivity and specificity of the screener in the population in which it is to be used. Using data from 755 normal individuals (1510 eyes), we calculated the PP+ of the Henson CFS2000 screening programme for a population aged 50 and over. 4.3% of normal eyes failed the screening programme. Ignoring one or two misses on the screening programme immediately adjacent to the disc reduced this figure to 1.3% and significantly improved the PP+ of the programme. Calculations of the PP+ at increasing glaucoma prevalence levels indicates this to be particularly relevant at low levels such as those encountered when screening middle aged and elderly populations. Optometrists should perform routine field analysis when screening for glaucoma provided they adhere to strict protocols. ...
NovaVision VRT Vision Restoration Therapy (VRT) is a computer-based training program developed to improve visual function in patients with visual field defects due to brain damage. By presenting thousands of visual stimuli at the border of the visual field defect and simultaneously giving little stimulation to the intact sector of the visual field, VRT attempts to improve function in areas of residual vision that may not be appreciated or perhaps may be neglected by the patient; i.e., areas of relative defect.
Authors: Gall, Carolin , Mueller, Iris , Gudlin, Julia , Lindig, Anja , Schlueter, Dorothee , Jobke, Sandra , Franke, Gabriele H. , Sabel, Bernhard A. Article Type: Research Article Abstract: Purpose: The aim of the study was to examine if improvements of stimulus detection performance in visual field tests after intensive visual training of the visual field border zone in patients with visual field defects are associated with changes in self-reported vision- and health-related quality of life (QoL). Methods: We studied a clinical sample of 85 patients suffering from visual field loss after brain damage that underwent repetitive, daily light stimulation (vision restoration training, …VRT) of the visual field border and the blind visual field for up to 75 hrs (N = 16) or 150 hrs (N = 69). Stimulus detection was quantified in the central visual field with a campimetric method before and after intervention. Health-related QoL was assessed by the Health-Survey SF-36 and vision-related QoL by the ...
3 study visits. Visit 1: Baseline visit for consent, getting baseline data and finally randomizing the patient. Those randomized to intervention get their first session of simulated visual field (2 per eye) on a regular computer for training purposes.. Visit 2: 1 to 2 days after baseline. The intervention group gets 1 practice test per eye. Then both groups get a regular automated visual field Visit 3: 1 to 2 weeks after baseline. The intervention group gets 1 practice test per eye. Then both groups get a regular automated visual field.. Study Ends, patient gets seen by the patient. ...
In the visual cortex, the representation of central visual space is supplied by matching geniculate inputs that are driven exclusively by one eye or the other. In layer 4 of early visual areas (V1 in primates and V1 and V2 in cat), these inputs form a nearly uniform array of small ocular dominance domains, while preserving overall topographic order within the cortical map. In ferret, however, ocular dominance domains in different regions of the visual cortex are strikingly irregular in size and shape. The exceptionally large size of domains in some regions implies a departure from the usual visuotopic matching of inputs from the two eyes. Using optical-imaging, electrophysiological, and anatomical techniques, we show that this regional variation is attributable to exclusively monocular maps of the central portions of the ipsilateral visual field in V1 and the contralateral visual field in V2. In addition, we document a complex interdigitation of V1 and V2 that entails a discontinuity in the ...
The location of VF damage did not clearly influence the degree of balance impairment in our study. When considering visual dependence of balance as an outcome, worse IVF sensitivity or more peripheral points missed in the superior and inferior VFs were each associated with lower visual dependence when evaluated in separate models, though neither stood out as uniquely important in models designed to test for the independent importance of damage in each region. With regards to RMS sway, superior VF damage, but not inferior VF damage, was associated with AP and ML sway when both were considered in a single model. However, high collinearity was noted in these models (VIFs of 4.2-4.3 and 2.3-2.4 for models evaluating central and peripheral VF loss, respectively), suggesting that the derived regression coefficients may not be meaningful. Furthermore, when the difference between superior and inferior VF damage was considered in models with overall damage included as a covariate, no association was ...
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In this study, we attempted to investigate the association of visual field defects with collisions with oncoming right-turning cars by testing patients with advanced glaucoma in a DS. Our results indicated that lower mean sensitivity in the inferior IVF hemifield contributed significantly to MVCs with oncoming right-turning cars in a DS.. Recently, a number of studies have described the importance of determining which areas of the visual field are associated with MVC involvement. Huisingh et al14 reported that drivers with a severely impaired lower or left field were more involved in MVCs, while Glen et al15 found that lowered performance in the hazard perception test (a part of UK driving examinations) was more strongly associated with defects in the upper visual field than the lower field. On the other hand, Yuki et al12 reported that central VF damage had no effect on MVCs; these studies have yielded conflicting results on which areas of the VF are most likely to be associated with MVCs. In ...
Norma Devine, Editor. On Wednesday, January 26, 2005, Dr. Rick Wilson, a glaucoma specialist at Wills, and the glaucoma chat group discussed Stages of Glaucoma Progression.. Moderator: Many believe that glaucoma damages the peripheral vision first, but glaucoma doctors and patients seem to have a different understanding of what peripheral means. Where does glaucoma first occur in the visual field and is that considered to be peripheral?. Dr. Rick Wilson: The visual field test that you all take extends out to 30 degrees from the center. Therefore, peripheral visual field loss on that test is only part way out to the 90 degrees that we see temporally. The earliest nerve damage secondary to early moderate nerve damage is usually above the center of vision, 15 to 20 degrees from the center, or in the nasal field 20 to 30 degrees from center. Remember that 35 to 45% of the optic nerve is damaged before consistent changes appear in the visual field.. P: Instead of saying that glaucoma affects ...
FRIDAY, Feb. 16, 2018 (HealthDay News) -- Patients of African descent with glaucoma have increased visual field variability compared to those of European descent, likely contributing to delayed detection of progression, according to a study published online Feb. 15 in JAMA Ophthalmology.. Carolina P.B. Gracitelli, M.D., Ph.D., from the University of California, San Diego, in La Jolla, and colleagues examined racial differences in longitudinal visual field variability in a multicenter prospective observational cohort study. Data were included for 236 eyes of 173 individuals of European descent and 235 eyes of 171 individuals of African descent. Participants were followed for a mean of 7.5 years.. The researchers found that the eyes of individuals of African descent had a larger mean standard deviation of the residuals than eyes of individuals of European descent (1.45 versus 1.12 dB). A larger increase in variability with worsening disease was seen in the eyes of individuals of African descent. ...
The V4 RF profile represents a constant-sized, circular sampling of the V1 surface distribution of the visual field (Motter, 2009). Because the visual field representation across the V1 surface is based on the cortical magnification factor (CMF), there is a radial expansion of the receptive field for V4 (and potentially all cortical areas sampling from V1). Figure 1 illustrates a model V4 RF centered at 4° in the periphery in the lower right visual quadrant; the scaling for the RF is in degrees of visual angle. The RF model was constructed based on a circular sampling of the V1 surface model (Motter, 2009) centered 4° into the periphery and proceeding in 1 mm concentric steps from 1 to 7 mm along the surface. The nested contours represent those steps and generally equate with the sensitivity contours within the RF; sensitivity decreases away from the RF center. The location of highest sensitivity is defined as the RF center even though its location is displaced toward the fovea as a result of ...
Formula 1: Small Safe Area for Web Content Most Web authors do not know how to translate visual field to pixels, which is what they generally can deal with. This technique provides that translation.. At this point in time, the most prevalent display is 1024 x 768 and about 15-17 inches diagonally. When viewed at a typical viewing distance (22-26 inches) a 10 degree visual field will capture an area approximately 341 x 256 pixels. This is not circular, but neither is the central vision of most users, and the difference is so small (and at the edge of the central vision where sensors are fewer) that it is not important.. Since the criterion is 25% of any 10 degree visual field, any single flashing event on a screen (there is no other flashing on screen) that is smaller than a contiguous area of 21,824 sq pixels (any shape), would pass the General and Red Flash Thresholds.. 1024 x 768 was chosen because it represents the most common screen size. It also works with higher resolution screens since ...
PURPOSE: To evaluate the influence of visual field (VF) examinations using modern techniques with short examination times on the intraocular pressure (IOP). METHODS: Sixty-one consecutive patients, aged 28-90 years, 40 women and 21 men, were examined
Discussion and Literature Review Case 1 demonstrated an important principle about smaller disks requiring a more thorough assessment. The patient had a seemingly normal neuroretinal rim area and CDR, however was experiencing glaucomatous visual field loss. Case 2 on the other hand had a larger disk, with an elevated CDR. However this was diagnosed as physiological cupping. This was confirmed by the normal visual field results. There are many techniques for clinically measuring disc size. Drance and Gross describe operating the 5 degree light spot of a direct ophthalmoscope which is 1.5 mm when projected over the disc. To determine which size of light spot is appropriate, one may stand 1m from the wall and the spot will have a diameter of 85 - 95 mm. When this spot size is projected over the optic nerve, if the disc fits on that target, the disc is normal. If the disc is smaller than that target, the disc is small. And if the disc is larger than the target, it is a large disc [2]. This technique ...
One hundred and thirty patients of cerebrovascular accidents were subjected to a visual field examination using a Static Campimeter and a Goldmann perimeter. Thirty seven cases of homonymous field...
A visual field examination is an examination designed to verify the integrity of the range of vision for each eye, including central and peripheral vision. This examination is an important integral part of every comprehensive visual examination conducted at City Eye Center, especially screening for glaucoma, retinal diseases and diseases related to damage to the optic pathway in the brain. The test is performed by distinguishing light points in space, with a device called a field of view meter that summarizes the results in a computer. This computer gives a general picture of the patients...Read more ...
Cranial Nerve 1- Olfaction This patient has difficulty identifying the smells presented. Loss of smell is anosmia. The most common cause is a cold (as in this patient) or nasal allergies. Other causes include trauma or a meningioma affecting the olfactory tracts. Anosmia is also seen in Kallman syndrome because of agenesis of the olfactory bulbs. Cranial Nerve 2- Visual acuity This patientâs visual acuity is being tested with a Rosenbaum chart. First the left eye is tested, then the right eye. He is tested with his glasses on so this represents corrected visual acuity. He has 20/70 vision in the left eye and 20/40 in the right. His decreased visual acuity is from optic nerve damage. Cranial Nerve II- Visual field The patients visual fields are being tested with gross confrontation. A right sided visual field deficit for both eyes is shown. This is a right hemianopia from a lesion behind the optic chiasm involving the left optic tract, radiation or striate cortex. Cranial Nerve II- Fundoscopy ...
Cranial Nerve 1- Olfaction This patient has difficulty identifying the smells presented. Loss of smell is anosmia. The most common cause is a cold (as in this patient) or nasal allergies. Other causes include trauma or a meningioma affecting the olfactory tracts. Anosmia is also seen in Kallman syndrome because of agenesis of the olfactory bulbs. Cranial Nerve 2- Visual acuity This patientâs visual acuity is being tested with a Rosenbaum chart. First the left eye is tested, then the right eye. He is tested with his glasses on so this represents corrected visual acuity. He has 20/70 vision in the left eye and 20/40 in the right. His decreased visual acuity is from optic nerve damage. Cranial Nerve II- Visual field The patients visual fields are being tested with gross confrontation. A right sided visual field deficit for both eyes is shown. This is a right hemianopia from a lesion behind the optic chiasm involving the left optic tract, radiation or striate cortex. Cranial Nerve II- Fundoscopy ...
Visual Fields: Examination and Interpretation by Thomas J Walsh, M.D. starting at $3.98. Visual Fields: Examination and Interpretation has 3 available editions to buy at Alibris
List of 13 disease causes of Bilateral visual field error, patient stories, diagnostic guides. Diagnostic checklist, medical tests, doctor questions, and related signs or symptoms for Bilateral visual field error.
This third edition of Visual Fields: Examination and Interpretation contains revisions and updates of earlier material as well as a discussion of newer techniques for assessing visual field disorders.
The Oculus Easyfield is an exciting new compact perimeter to do static perimetry up to 30°. It has been designed for the combined use as a visual field screener and perimeter, offering features usually available only in large units. The Easyfields integrated bowl with a 11.81 (30 cm) radius and distance corrected lens is adapted to the Goldman standard and fulfills the ISO-norm 12866 for perimeters. The Easyfield has a fixed point grid with 135 test locations including 30-2. The unit offers various testing methods including: · Fast Threshold (3 minutes) · Normal Threshold (6 minutes), and · Supra-threshold with numerous testing strategies.. Available:. ...
88 eyes of 48 consecutive patients were included for study, 20 male and 28 female, aged 57-94 (avg. 79). All patients had glaucomatous optic nerve cupping and/or glaucomatous visual field loss prior to treatment. Pretreatment, IOPs ranged 6-23mm Hg (avg. 13) on 0-3 (avg. 1.6) medications. 33 eyes had had prior glaucoma surgery. Snellen visual acuities (VA) ranged 20/15 to count fingers (median 20/60). Prior to treatment, both VEPs and ORPs of all eyes were abnormal. Following panmacular SDM, VA and IOP were unchanged, while VEP amplitudes (p=0.001) and automated perimetry by ORP ( ...
Positron emission tomography (PET) was used to identify the neural systems involved in shifting spatial attention to visual stimuli in the left or right visual field along foveofugal or foveocentric directions. Psychophysical evidence indicated that stimuli at validly cued locations were responded to faster than stimuli at invalidly cued locations. Reaction times to invalid probes were faster when they were presented in the same than in the opposite direction of an ongoing attention movement. PET evidence indicated that superior parietal and superior frontal cortex were more active when attention was shifted to peripheral locations than when maintained at the center of gaze. Both regions encoded the visual field and not the direction of an attention shift. In the right superior parietal lobe, two distinct responses were localized for attention to left and right visual field. Finally, the superior parietal region was active when peripheral locations were selected on the basis of cognitive or ...
Australian demographic studies show that visual impairment contributes significantly to elderly disability. Visual field loss due to glaucoma, the sec
Binasal occlusion is a method of partial covering (occlusion) of the visual field of the two eyes in which the sector of the visual field that is adjacent to the nose (the nasal visual field) is occluded for each eye. It is a well-known procedure in vision therapy.
Definition of Peripheral vision loss in the Financial Dictionary - by Free online English dictionary and encyclopedia. What is Peripheral vision loss? Meaning of Peripheral vision loss as a finance term. What does Peripheral vision loss mean in finance?
In patients with glaucoma, frequent visual field testing may be associated with earlier detection of the conditions progression, according to a report published Online First by Archives of Ophthalmology, one of the JAMA/Archives ...
TY - JOUR. T1 - Risk factors for visual field progression in treated glaucoma. AU - De Moraes, Carlos Gustavo V. AU - Juthani, Viral V.. AU - Liebmann, Jeffrey M.. AU - Teng, Christopher C.. AU - Tello, Celso. AU - Susanna, Remo. AU - Ritch, Robert. PY - 2011/5. Y1 - 2011/5. N2 - Objective: To determine intraocular pressure (IOP)-dependent and IOP-independent variables associated with visual field (VF) progression in treated glaucoma. Design: Retrospective cohort of the Glaucoma Progression Study. Methods: Consecutive, treated glaucoma patients with repeatable VF loss who had 8 or more VF examinations of either eye, using the Swedish Interactive Threshold Algorithm (24-2 SITA-Standard, Humphrey Field Analyzer II; Carl Zeiss Meditec, Inc, Dublin, California), during the period between January 1999 and September 2009 were included. Visual field progression was evaluated using automated pointwise linear regression. Evaluated data included age, sex, race, central corneal thickness, baseline VF mean ...
There is a long list of eye diseases and conditions affecting the field of vision, among them glaucoma. Glaucoma is defined as a disease causing damage to the optic nerve with resulting visual field defects, characterized by slow progression [1]. Glaucoma causes damage to the optic disc, which leads to visual field defects.. The visual field is of great importance while driving; a limited field of vision hinders the drivers capability of not only detecting objects in the periphery, but also judging distances and speed. Studies have shown that drivers with limited fields of vision have significantly poorer driving capabilities with regard to speed adjustment with lane changes, maintaining lane positions in a curve, as well as anticipatory skills [2].. Until now, there has not been a specific testing method required by the Swedish Transport Agency, and the requirement that was specified was stated simply that the applicants binocular visual field must be at least equivalent to a normal visual ...
TY - JOUR. T1 - Cognitive task to differentiate between visual field deficit and neglect. AU - Balconi, Michela. AU - Sozzi, Matteo. AU - Corbo, Massimo. PY - 2016. Y1 - 2016. N2 - Neglect patients are able to process visual stimuli even if they do not have an overt perception of them. Indeed, since first studies at the end of 80 s lot of works demonstrated the presence of an implicit information processing, specifically part of them focused on the presence of a semantic activation effect due to the onset of a prime (either word or picture) in neglected space. This kind of effect was not found in patient with visual field deficits. Actually hemianopia determines a variable reduction of visual field width and a consequent partial blindness for the patient. Even though there are different neuroanatomical substrates between neglect and hemianopia, we know that clinical examination (including neuropsychological assessment) may provide confounding results. Not so many studies tried to disentangle ...
Visual field deficit (VFD) is one of the most commonly observed symptoms following brain injury. Persistent VFD and defective exploratory oculomotor scanning patterns often cause severe impairment in daily activities, particularly as regards visual exploration and reading. Homonymous hemianopia is consequently a powerful negative predictor of patient outcome. In spite of these quantitative and qualitative factors, there currently exists no consensus on rehabilitative therapy and treatment. Different approaches have nevertheless been developed, all of them having one therapeutic principle in common; repeated practice of a specific visual task, with the hope/expectation that improved performance will extend to a wide range of ecologically useful visual functions. The four main available methods aim at replacing part of the intact visual field with part of the damaged visual field (optical therapy using prisms), at partially restoring the lost visual field region (restorative therapies), at stimulating
The paper by Krauss et al (this issue, pp 339-343)1 helps to settle a controversy that has been simmering in the epilepsy world for several years.1 Initial reports that vigabatrin use was associated with irreversible visual field defects evoked scepticism. Various voices held that such visual field defects were not uncommon in patients with epilepsy and might be associated with epilepsy itself rather than from specific drug treatment. Evidence has now accumulated to convince all but the most sceptical that the antiepileptic drug vigabatrin, an irreversible inhibitor of GABA transaminase, has a strong tendency to produce visual field constriction by a toxic effect on the retina, although the precise mechanism by which it does so has yet to be identified. It is not clear either why a small minority of patients develop visually disabling field constriction while in most subjects visual field defects are mild and asymptomatic or indeed completely undetectable. It does not appear that such visual ...
The cerebral cortex changes throughout the lifespan, and the cortical grey matter in many brain regions becomes thinner with advancing age. Effects of aging on cortical thickness have been observed in many brain regions, including areas involved in basic perceptual functions such as processing visual inputs. An important property of early visual cortices is their topographic organization - the cortical structure of early visual areas forms a topographic map of retinal inputs. Primary visual cortex (V1) is considered to be the most basic cortical area in the visual processing hierarchy, and is topographically organized from posterior (central visual representation) to anterior (peripheral visual representation) along the calcarine sulcus. Some studies have reported strong age-dependent cortical thinning in portions of V1 that likely correspond to peripheral visual representations, while there is less evidence of substantial cortical thinning in central V1. However, the effect of aging on cortical
Purpose: To determine the extent to which the 24-2 visual field (VF) misses macular damage confirmed with both 10-2 VF and optical coherence tomography (OCT) tests and to evaluate the patterns of damage missed. Methods: One hundred forty-one eyes of 141 glaucoma patients or suspects underwent 24-2 VF (mean deviation [MD] better than −6 dB), 10-2 VF, and OCT testing. Retinal nerve fiber layer (RNFL) and retinal ganglion cell plus inner plexiform (RGC+) probability plots were combined with 10-2 VF probability plots. Eyes were classified as abnormal macula if abnormal regions on both the 10-2 VF and OCT plots agreed. The number of abnormal eyes missed (i.e., false negatives) was determined for the following 24-2 VF metrics: MD; pattern standard deviation (PSD); glaucoma hemifield test (GHT); cluster criteria (CC); and abnormal points within ± 10°. Eyes that were missed on one or more of the 24-2 metrics were classified by damage type based upon circumpapillary RNFL thickness plots. Results: ...
PURPOSE To investigate effects of cataract extraction and intraocular lens placement on the visual field of eyes with chronic open-angle glaucoma. METHODS A retrospective review was conducted of 41 eyes of 41 patients with visually significant cataract and chronic open-angle glaucoma who had undergone automated static perimetry within 6 months before and 6 months after phacoemulsification with intraocular lens placement. RESULTS Comparison of preoperative and postoperative testing showed that the mean visual acuity, foveal threshold, and mean deviation improved significantly (P | .0001), while the mean pattern standard deviation and corrected pattern standard deviation worsened significantly (P | or = .03). Eyes not receiving miotics preoperatively did not have a significant postoperative change in the mean pattern and corrected pattern standard deviations. Increasing severity of glaucoma-related visual field loss was significantly associated with less improvement in the postoperative mean deviation
b>PURPOSE. To evaluate the diagnostic power of conventional, achromatic, automated perimetry (CAP), shortwavelength automated perimetry (SWAP), frequency-doubling technology (FDT) perimetry, and visual evoked potentials (VEP) in a group of patients with multiple sclerosis (MS) with or without a history of optic neuritis. METHODS. Thirty eyes of 15 patients (5 male, 10 female, average age 387 years) with confirmed diagnosis of MS underwent CAP, SWAP (Humphrey 750-II VFA, program central 30-2, full-threshold strategy), FDT perimetry (program N-30), and pattern VEPs. Sixteen eyes (53.3%) had no history of ocular involvement and a negative ophthalmologic examination. They were matched with a control group of 10 healthy volunteers (4 male, 6 female, average age 3110 years). The mean deviation (MD) and the pattern standard deviation (PSD) of the two groups were compared (t-test). Fourteen eyes (46.7%) had, on the contrary, a history of optic neuritis. Inside this group, the MD and the PSD of the three ...
article{d8a75dbb-7b8b-4e72-a461-f9d11ed9d7e0, abstract = {,p,PURPOSE: To establish and evaluate inter-subject variability and normal threshold limits for the new SITA strategies and to compare them with those obtained with the traditional Humphrey Full Threshold algorithm.,/p,,p,METHODS: Data from 330 eyes of 330 normal subjects were collected at 10 centres in order to establish limits of normality for the new SITA strategies and thus, to make it possible to subject SITA fields to computer-assisted visual field analysis. Two visual field tests were obtained with each of the SITA Standard, SITA Fast, and the Full Threshold algorithms.,/p,,p,RESULTS: Inter-subject variance was 31% smaller with SITA Standard and 41% smaller with SITA Fast than with Full Threshold (p<0.0001). Age-dependent decrease of differential light sensitivity was also significantly smaller with both SITA algorithms than with Full Threshold (p<0.0001), 23% and 25% respectively. Mean sensitivity was somewhat higher with ...
Both eyes of each participant were included. Visits were scheduled every 6 months. At each visit, standard clinical ophthalmic examinations were performed, including visual acuity, intra-ocular pressure, gonioscopy and ophthalmoscopy. At each visit, standard automated perimetry was also performed. Visual fields were acquired on a Humphrey Visual Field Analyzer (Carl Zeiss Meditec) with a standard white-on-white 24-2 field with the full threshold program. The provided data set contains information on the visual field and on the individual visual field test locations ...
TY - JOUR. T1 - Compression and suppression of shifting receptive field activity in frontal eye field neurons. AU - Joiner, Wilsaan. AU - Cavanaugh, James. AU - Wurtz, Robert H.. PY - 2013/11/15. Y1 - 2013/11/15. N2 - Before each saccade, neurons in frontal eye field anticipate the impending eye movement by showing sensitivity to stimuli appearing where the neurons receptive field will be at the end of the saccade, referred to as the future field (FF) of the neuron. We explored the time course of this anticipatory activity in monkeys by briefly flashing stimuli in the FF at different times before saccades. Different neurons showed substantial variation in FF time course, but two salient observations emerged. First, when we compared the time span of stimulus probes before the saccade to the time span of FF activity, we found a striking temporal compression of FF activity, similar to compression seen for perisaccadic stimuli in human psychophysics. Second, neurons with distinct FF activity also ...
This graph shows the total number of publications written about Visual Field Tests by people in Harvard Catalyst Profiles by year, and whether Visual Field Tests was a major or minor topic of these publication ...
Background: Glaucoma is a common cause of visual impairment and blindness. The Heidelberg Retinal Tomogram (HRT) evaluates the structural details of the optic disc and has been widely investigated as a research tool in imaging of the ONH. The correlation between the perimetry and HRT data in Caucasian eyes has been reported previously. Objective: To correlate the HRT parameters and visual field indices in Indian eyes including established glaucoma and glaucoma suspect patients. Methods: Eighty-three eyes of 50 patients having primary open angle glaucoma underwent automated Humphrey perimetry (30-2) and confocal scanning laser ophthalmoscopy (HRT II). The global visual field indices and the HRT II parameters were correlated. Results: The average MD of the study group was -3.70 ± 3.99dB (range 1.11 to -19.54). The correlations between global parameters by HRT and global visual field indices were found to be significant for rim area, rim volume, height variation contour, mean RNFL thickness and ...
Nonorganic vision loss is common but can be challenging to diagnose and treat. In this chapter, we begin by reviewing the clinical features that suggest nonorganic vision loss. We next describe the maneuvers that can be used to demonstrate intact visual function in the patient who reports decreased visual acuity in one or both eyes. We then describe strategies to evaluate the patient who has visual field constriction. We describe the features that help to distinguish organic visual field constriction from nonorganic visual field constriction. Lastly, we discuss the management approach, which includes reassuring the patient that there is no evidence of permanent damage to the visual system and a good prognosis for spontaneous recovery.
We also tested whether species exhibit a behavioral compensation for anterior blind areas by yawing the head. During swimming the head yaws left and right thus expanding the viewable space in both the anterior and posterior directions (see Movie 1 in supplementary material). Both hammerhead species exhibit greater head yaw in the horizontal plane than the carcharhinids and the amount of yaw increased proportionately with head width. There exists then the potential for spatial information provided by the left and right eyes to be temporally integrated to generate a composite visual field that exceeds the dimensions of the static visual field. The cumulative effect of maximum eye rotation and maximum head movement reduces blind areas and thereby enlarges the extent of the visual field. Head yaw was calculated on sharks in non-excited conditions, which probably under-represent the degree of yaw exhibited while actively searching for prey. An exaggerated head yaw requires a proportionately greater ...
PRéCIS: The C3 fields analyzer (CFA) is a moderately reliable perimeter preferred by patients to standard perimetry. While it does not approximate the gold standard, it was sensitive and specific for clinically defined glaucoma (area under the receiving operator characteristic curve=0.77 to 0.86). PURPOSE: Testing the visual field is a vital sign for diagnosing and managing glaucoma. The current gold standard, the Humphrey visual field analyzer (HFA), is large, expensive and can be uncomfortable for some patients. The current study investigated the CFA, a virtual reality head-mounted visual field testing device, as a possible subjective field test for glaucoma screening and eventually glaucoma monitoring. PATIENTS AND METHODS: The CFA presented stimuli in the same 54 positions as the HFA 24-2 SITA Standard test using a suprathreshold algorithm approximating an 18 dB deficit. A total of 157 patients (both controls and glaucoma patients) at the Aravind Eye Hospital, Pondicherry, India, were ...
Sensory areas of adult cerebral cortex can reorganize in response to long-term alterations in patterns of afferent signals. This long-term plasticity is thought to play a crucial role in recovery from injury and in some forms of learning. However, the degree to which sensory representations in primary cortical areas depend on short-term (i.e., minute to minute) stimulus variations remains unclear. A traditional view is that each neuron in the mature cortex has a fixed receptive field structure. An alternative view, with fundamentally different implications for understanding cortical function, is that each cells receptive field is highly malleable, changing according to the recent history of the sensory environment. Consistent with the latter view, it has been reported that selective stimulation of regions surrounding the receptive field induces a dramatic short-term increase in receptive field size for neurons in the visual cortex [Pettet, M. W. & Gilbert, C. D. (1992) Proc. Natl. Acad. Sci. ...
Patient with Macular Disease, Good Visual Acuity, and Central Visual Field Disruption and Significant Difficulties with Activities of Daily Living, Online,
The first stage of visual processing in the cortex is called V1. In primates, V1 creates a saliency map (highlights what is important) from visual inputs to guide the shifts of attention known as gaze shifts.[13] It does so by transforming visual inputs to neural firing rates from millions of neurons, such that the visual location signalled by the highest firing neuron is the most salient location to attract gaze shift. V1s firing rates are received by the superior colliculus (in the mid-brain) which reads out the V1 activities to guide gaze shifts. V1 has a very well-defined map of the spatial information in vision. For example, in humans, the upper bank of the calcarine sulcus (in the occipital lobe) responds strongly to the lower half of visual field (below the center), and the lower bank of the calcarine to the upper half of visual field. In concept, this retinotopic mapping is a transformation of the visual image from retina to V1. The correspondence between a given location in V1 and in ...
Method: Octopus 101 (grogramm G2) was used to determine localized BY sensitivity in a heterogeneous cohort of subjects: 25 perimetric OAG patients (glaucomatous optic disc atrophy and visual field defects in white-on-white perimetry), 52 preperimetric OAG patients (glaucomatous optic disc atrophy, no visual field defects in conventional perimetry), 52 patients with OHT, and 40 healthy control subjects. Age range: 30-70 years, AQ: 0.8-1.2, opacity lens meter in the normal range, one eye/subject. All subjects were experienced in conventional white-on-white (WW) perimetry, 35% had earlier BY perimetry. Age normalized defect-values have been calculated for all tests points using the results of an earlier multicenter study. Diagnostic value of tested areas have been judged from the area under the ROC-curve. Differences between localized white-on-white and BY results have been analyzed ...
How does vision therapy help a patient who has suffered a visual field loss due to a stroke? Take a look at our patient Darlene who just complete her vision rehabilitation. She tells her story best...
The visual pathway begins in the retina; impulses from the photoreceptors are transmitted to the optic chiasm via the optic nerve of each eye. Within the chiasm, the retinal fibers segregate into the right and left optic tracts. Each optic tract carries information for its respective field of vision. For example, the right optic tract consists of fibers from the ipsilateral temporal retina and the contralateral nasal retina. The corresponding hemifields represent the left half of the visual field for each eye. The optic tracts, whose cell bodies lie in the ganglion cell layer of the retina, go on to synapse at the lateral geniculate nucleus. The subsequent fibers further divide as they travel to the primary visual cortex (known variously as V1, striate cortex, or Brodmann area 17), where they terminate; the most inferior of the fibers (subserving the superior visual field) take one path and the more superior fibers (subserving the inferior visual field) follow a different one (Fig 3-8). Lesions ...
Binasal occlusion is a method of partial covering (occlusion) of the visual field of the two eyes in which the sector of the visual field that is adjacent to the nose (the nasal visual field) is occluded for each eye. It is a well-known procedure in vision therapy. By blocking parts of the image that would be seen by both eyes, binocular occlusion reduces the visual stress that would be related diplopia and binocular rivalry. In contrast to an eye patch that occludes the whole visual field of one eye, binocular occlusion allows some degree of binocular vision; more particularly, it emphasizes the role of binocular functioning in peripheral vision: objects that are located to the right can only be fixated by the right eye, and those located to the left only by the left eye. This in particular prevents the cross-fixation. Cross-fixation which occurs in some strabismus patients with esotropia, and is, in particular, characteristic for a form of infantile esotropia also known as Ciancis syndrome. ...
Longitudinal Glaucomatous Visual Fields. This data set contains IOP measurements and 24-2 Full Threshold visual fields obtained with a Humphrey Field Analyzer (Zeiss). Data of both eyes of 139 patients over a mean period of over 9 years is included, with on average more than 17 fields per eye. Local threshold and total deviation values are included ...
The system utilizes a reusable patient return adapter that connects the Ultravision™ generator to a standard electrosurgical unit, allowing both to utilize a common dispersive electrode (grounding pad). The system can be powered using a rechargeable battery or via AC power.. Optimal placement of the trocar is within 5 inches of the energy source producing smoke and particulates and with a direct line of sight to the operative field. Benefits of the use of this device include improved visual field, decreased need to vent insufflated gas to evacuate smoke and decreased need to clean laparoscope lens when soiled by particulate.. Animal studies: Simulated laparoscopy (50-100 min) were performed on porcine omentum using monopolar, bipolar and ultrasonic instruments. RCT: double-blinded, prospective trial (N=30) with six week follow-up (N=25) for patients receiving elective laparoscopic cholecystectomy. Primary endpoint was a clear visual field and secondary patient safety endpoints. Device found ...
Fundus automated perimetry is a technique that images the retina during visual field testing, enabling a correlation to be made between visual function and retinal structure.1. Advantages of Fundus Automated Perimetry over Standard Automated Perimetry include the possibility to measure sensitivity at specific retinal locations, higher accuracy thanks to retinal-tracking based compensation of eye movements and the simultaneous assessment of function (expressed by retinal sensitivity) and structure (images of the ONH, of the RNFL and of the retina). Fundus Automated Perimetry provides a simultaneous, quantitative assessment of fixation characteristics.. Use of Fundus Automated Perimetry in the clinical management of glaucoma has been limited so far, as available systems were lacking compliance with the standards of automated perimetry. COMPASS overcomes such limitations and brings visual field analysis to the next level!. In particular COMPASS, for the first time, extends field coverage to 30° + ...
TY - JOUR. T1 - Luminance-modulated adaptation of global flash mfERG: Fellow eye losses in asymmetric glaucoma. AU - Chu, Patrick H W. AU - Chan, Ho Lung Henry. AU - Brown, Brian. PY - 2007/6/1. Y1 - 2007/6/1. N2 - PURPOSE. To use the global flash multifocal electroretinogram (mfERG) in patients with asymmetric glaucoma to determine whether retinal function is affected in fellow eyes that have no glaucomatous visual field defects. METHODS. Forty normal subjects and 12 patients with asymmetric glaucoma were recruited for visual field and mfERG measurement. The mfERG was assessed by using a global-flash stimulation paradigm with four video frames: 103 scaled hexagonal elements followed by a dark frame, a global-flash frame, and a dark frame. The localized luminance difference was set at 96%, 65%, 49%, and 29% display contrast during the four different test conditions, respectively. The first-order kernel response was measured, and the adaptive index which has been used previously was calculated. ...
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We report the results of a survey and consensus process to determine the three most favoured perimetry programs deemed best suited for the visual field assessment in four neurological conditions (chiasmal compression, IIH, optic neuropathy and stroke) that commonly present to eye clinics. This is the second stage of a programme of research (PoPiN) for this purpose. The first stage was a systematic review to identify patterns of visual field loss and types of perimetry programs used to assess visual fields in four common neurological conditions. The systematic review identified 20 programs which populated this survey and consensus process, with an additional 27 obtained from manufacturer perimeter manuals (Hepworth & Rowe 2018). The survey fullfied its role of narrowing perimetry programs across the four target conditions in advance of subsequent discussion of these in a consensus meeting.. Following the consensus meeting the same three programs were selected as most favoured for use in three of ...
Validated by more than 25 years of research, design and clinical experience, the Humphrey Field Analyzer (HFA) is the accepted standard of care in glaucoma diagnosis and management. With over 65,000 installed units worldwide, the HFA is the premier automated visual field analyzer.
In a previous study, the team revealed that dietary omega-3 intake had an effect on retaining central visual field sensitivity. They found that individuals receiving _-3 intake of at least 0.20 g/d, in conjunction with vitamin A palmitate, 15,000 IU/d had nearly a 50% slower rate of decline in central visual field sensitivity than patients receiving a lower omega-3 intake and the same dose of vitamin A ...
... 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 ... Manji, H.; Plant, G. T. (1 January 2000). "Epilepsy surgery, visual fields, and driving: a study of the visual field criteria ...
"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 ...
Today, in the visual system the left visual field is represented in the right hemisphere and the right visual field in the left ... Now the right visual field of the eye reaches the left part of the retina but still the left hemisphere, and vice versa. This ... Furthermore, the visual fields are represented upside down in the brain. The physical cause is only the change from a convex ... This leads to an inverted representation of the visual fields in the brain - they crosse sides and are represented upside down ...
... 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. Longuet-Higgins, H. C. (1982). "The role of the vertical ... 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. Other animals that are not necessarily predators, such as fruit ...
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- ... A formal visual field test is performed. The retinal nerve fiber layer can be assessed with imaging techniques such as optical ...
... 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 ...
"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, 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 ... Birds with eyes on the sides of their heads have a wide visual field, useful for detecting predators, while those with eyes on ... The cost of this adaptation is that they have myopia in the lower part of their visual field. Birds with relatively large eyes ...
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. In ... 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 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 ...
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, ... ISBN 978-0-7817-4596-3. Park, S. J.; Park, K. H.; Heo, J. W.; Woo, S. J. (2014-03-01). "Visual and anatomic outcomes of golf ...
... and neural regeneration and repair fields. Much of his work is focused on the visual system, including the mechanisms ... "Mechanisms Underlying Development of Visual Maps and Receptive Fields". Annual Review of Neuroscience. 31 (1): 479-509. doi: ... After moving to Stanford in 2016, Huberman discovered and published the use of non-invasive methods such as visual stimulation ... His lab pioneered using genetic tools to study the visual system function, development and disease. Among the Huberman Lab's ...
McComb, D.M. & S.M. Kajiura (2008). "Visual fields of four batoid fishes: a comparative study". Journal of Experimental Biology ... ISBN 1-55209-629-7. Parsons, G.R. (2006). Sharks, Skates, and Rays of the Gulf of Mexico: A Field Guide. University Press of ... ISBN 1-57806-827-4. McClane, A. J. (1978). McClane's Field Guide to Saltwater Fishes of North America. Macmillan. p. 45. ISBN 0 ...
Visual-tactile perceptive fields overlap in processing this space. For example, an individual might see a feather as not ... Visual code: This category denotes the amount of eye contact between participants. Four sub-categories are defined, ranging ... Whereas Hall's work uses human interactions to demonstrate spatial variation in proxemics, the field of neuropsychology ... Ambient-extrapersonal space initially courses through the peripheral parieto-occipital visual pathways before joining up with ...
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 ...
"Welcome to the Visual and Autonomous Exploration Systems Research Laboratory". "Visual and Autonomous Exploration Systems ... "for outstanding contributions in the field of ophthalmology and vision sciences with particular focus on diagnostics and ... The center enacted the only FDA-approved visual prosthesis to date (Argus retinal prosthesis or ARGUS II). Co-winner of USDOE/ ... where he founded Caltech's Visual and Autonomous Exploration Systems Research Laboratory. He also held concurrent appointments ...
During a field test in Africa, disaster strikes when the Sidewinder disturbs the crust that has formed above a burning pit, ... London, UK: Visual Imagination. p. 42. ISSN 0958-7128. Archer and Hearn, p. 120. Hearn, pp. 73, 179. Hearn, p. 179. " ...
Grahanandan Singh, 88, Indian Olympic field hockey player. Khalil Ullah Khan, 80, Bangladeshi film and television actor. Tommy ... Southland rugby legend Jack Hazlett dies aged 76 National Artist for Visual Arts Imao passes away Karl-Heinz Kurras gestorben ( ... Dick Loggere, 93, Dutch Olympic field hockey player, silver medallist (1952) and bronze medallist (1948). J. B. Moraes, 81, ...
In this project the role of art and visual culture in the context of colonial practices was explored. The project consisted of ... It contains contributions by national and international specialists in the field. Some exhibitions are, apart from the ...
The school also produced a number of athletes competing in track and fields at state, national and international level. Faris ... However, a range of additional subjects are offered for interested students including Principles of Accounting and Visual Arts ... In the non-academic field, the school declared its niche areas in hockey, golf, traditional Malay musical orchestra. ...
Each episode covers a single topic from history and shows connections between that topic and various fields of science and ... Chris Ramirez Visual Effects Supervisors Matt Drummond, Christopher Gaal, John R. McConnell Compositors Dean Guiliotis, Carter ... Higgins, Brad Moylan, Ian Pauly Lead 3D Visual Effects Artist Michael Ranger 3D Artist Scott Bell, Jennie Bozic, Keith ...
The ratio of red/infrared light refraction is displayed as a visual signal on a computer monitor and may also be translated ... Hemoencephalography (HEG) is a neurofeedback technique in the field of neurotherapy. Neurofeedback, a specific form of ... which then calculates the ratio of red to infrared light and translates it into a visual signal of corresponding to oxygenation ...
Geiger Field, Washington, 1 June 1943 Rapid City Army Air Base, South Dakota, c. 13 June 1943 Pendleton Field, Oregon, 10 ... The 731st flew night bombing missions at all altitudes, using both visual and radar techniques. Its Invaders also flew close ... 6 August 1945 Sioux Falls Army Air Field, South Dakota, c. 12-28 August 1945 Long Beach Army Air Field (later Long Beach ... On 14 July 2022, one MQ-9 of the squadron crashed in a field south of the base while conducting a routine mission in the region ...
Bignante, Elisa (2010-02-24). "The use of photo-elicitation in field research". EchoGéo (in French) (11). doi:10.4000/echogeo. ... Also known as "participatory photography" or "photo novella", photovoice is considered a sub-type of "participatory visual ... Photovoice uses participant photography to guide interviews, and is commonly used in the fields of community development, ... Lorenz, LS and B Kolb (2009). Involving the public through participatory visual research methods. Health Expectations, Volume ...
These schools that are affiliated to DBSE provide education in different fields. There are 12 schools for STEM , 7 schools for ... Humanities, 4 schools for "Performing & Visual Arts", 7 schools for "High End 21st Century Skills" and 1 school for Armed ...
"Visual Diagnostic Skills Program". Music for the Church. GIA Publications, Inc. 2018. Retrieved February 8, 2018. Sanders, ... both as a commercial tool and one for re-training unemployed workers in new fields. Norris refused to give up on the system, ... William H. (1979). The effect of computer-based instructional materials in a program for visual diagnostic skills training of ... "A comparison of three approaches to the teaching of auditory-visual discrimination, sight singing and music dictation to ...
The Epcot International Festival of the Arts, inaugurated in 2017, is a festival showcasing visual, culinary, and performing ... Walt Disney World Ambassador Genie Field introduced E. Cardon Walker, Disney's chairman and CEO, who dedicated EPCOT Center. ... and the visual and culinary arts. Spaceship Earth, an eighteen-story-tall geodesic sphere structure and the anchor pavilion, ...
"Field Experience With Annex K - Bounds Checking Interfaces". Retrieved 5 November 2015. "MSC06-C. Beware of compiler ... "Repel Attacks on Your Code with the Visual Studio 2005 Safe C and C++ Libraries". Retrieved 13 February 2015. "The C11 standard ... they were implemented only on Windows and at the same time warning messages started to be produced by Microsoft Visual C++ ...
... : Visual communications design Bachelor of Design: Product Design Bachelor of Design: Design and Digital Arts ... or B.Design) degree is usually an undergraduate academic degree in the field of design awarded for a course or major that ... ". "תואר בעיצוב תקשורת חזותית" [First Degree in Visual Communications Design]. (in Hebrew). Archived from the ...
They have created the theme songs for many Japanese adult games, most famously the opening "Tori no Uta" to the visual novel ... Cleanup tagged articles with a reason field from June 2012, Wikipedia pages needing cleanup from June 2012, Articles lacking ... Although production for the game was later cancelled, they were able to establish ties with Visual Art's, a computer game and ... The first game I've produced music for was Hakidame: Trash, produced by Zero (a brand of Visual Art's), released in February ...
The school runs courses in Business, Science, general arts, general agric, Home Economics and visual arts, leading to the award ... standard field for soccer and athletics, basketball court, volley and handball court) School Clinic Barbering shop Africa ... 3 Science Laboratories ( Physics, Biology and Chemistry) I.C.T Lab Library Home Economics Lab Visual Arts Center School Farm ... The school has about 2,500 students enrolled in Business, Science, general arts, general agric, Home Economics and visual arts ...
WinterIsComing #Belfast #Irishthrones Just a casual walk amongst the green fields of Corbet and i bump into these people!!". ... Giardina, Carolyn (February 13, 2018). "Visual Effects Society Awards: 'War for the Planet of the Apes' Wins Big". The ...
For the second consecutive year, the field of major nominees included at least one blockbuster at the American and Canadian box ... John Barry - Composer Grant McCune - Visual effects Tony Curtis - Actor Edward Limato - Agent Tom Mankiewicz - Writer Gloria ...
... and visualization and visual interfaces. She is a Professor Emerita of Computer and Information Science and a member of the ... a field of computer science that she has helped pioneer, and, in particular, pointing devices and haptic interactions, WWW ...
This afforded a more detailed view over a smaller region of the visual field. WFC and PC images are typically combined, ... Other HST instruments : Wide Field and Planetary Camera - Former instrument on the Hubble Space Telescope Wide Field Camera 3 ... and the Hubble Deep Field South in 1998. During STS-125, WFPC2 was removed and replaced with the Wide Field Camera 3 as part of ... The Wide Field and Planetary Camera 2 (WFPC2) is a camera formerly installed on the Hubble Space Telescope. The camera was ...
The number of studies in this field has blossomed contemporaneously with greater gender studies, and a degree of tension exists ... visual novels, and some vehicle simulation games, among others. These games are generally less frequently described as non- ... visual novels, and traditional games. Examples of traditionally non-violent games include: Sudoku Gridmaster - A totally non- ... or playing violent video games deemed to contain any visual depiction or representation of realistic injury to a human or a " ...
Gina Adams (born 1965) - A visual artist and assistant professor at Emily Carr University, Adams claims White Earth Ojibwe and ... and field researcher who was promoted as the last fluent speaker of the Catawba language, but was later revealed to have ... you get to wear all year long and benefit from professionally because it checks that box that was created to even-out the field ...
Men's Field Kyrgyzstan at the 2016 Summer Olympics "Paralympics categories explained". ABC. 3 September 2008. Retrieved 25 ... visual impairment, including blindness; Les autres, any physical disability that does not fall strictly under one of the other ...
Herbert Johnson devised a new cap with soft top that would be practical for field operations. This was adopted as the dress cap ... The antelope sejant may represent a visual pun, for it is in the crest of the Capps family of Norfolk and Kent. Appointed ...
... he graduated Magna Plus Cum Laude in Visual and Environmental Studies in 1972 with his bachelor thesis being about the fields ... Harrison was born in Milwaukee, Wisconsin, He was exposed to artistic fields from a young age, his mother studied art and ... Harrison was introduced to Richman by mutual friend and journalist Danny Fields and the pair bonded over their shared love of ...
Its visual identity is derived from the four eras it underwent-austere Entropism, colourful Kitsch, imposing Neo-Militarism, ... The world is loaded with vertical streaming, a rendering technique that omits objects below and above the player's field of ... Huff, Lauren (29 January 2020). "The Lion King reigns at 2020 Visual Effects Society Awards". Entertainment Weekly. Archived ... visual quality, and freshness of the cyberpunk setting. The game's systems such as crafting, driving mechanics, and combat ...
While the field of neurorehabilitation is relatively new, many therapies are controversial, and while some are considered ... It may also include neuro-muscular strengthening and training, and visual perceptual skill development. Rehabilitation ... Neurorehabilitation is the culmination of many different fields to provide the best care and education for patients with ... have a wide variety of specialists in many different fields to provide the most well rounded treatment of patients. These ...
As Clark (1961) comments, the work is a perfect visual counterpart to John Milton's Paradise Lost, written in the same period. ... for Summer Boaz discovering Ruth gleaning corn in his fields from the Book of Ruth; for Autumn the Israelite spies returning ...
... retired track and field athlete Milt Campbell, former track and field athlete Henry Carr, former track and field athlete Andre ... American architects List of African-American pioneers in desegregation of higher education List of African-American visual ... retired track and field athlete Edwin Moses, retired track and field athlete Dave Neville, retired track and field athlete Dan ... retired track and field athlete Ronnie Ray Smith, former track and field athlete Tommie Smith, retired track and field athlete ...
Stanley Rouse added two more field goals. Ole Miss beat Florida with a "lucky pass." from Petty to Ap Applewhite. The starting ... The following chart provides a visual depiction of Florida's lineup during the 1926 season with games started at the position ... The highlights of the season were the Gators' two victories home field over the Florida Southern Moccasins and Clemson Tigers, ... Gators Lose To Kentucky On Hot Field". Sarasota Herald-Tribune. October 24, 1926. "Georgia Downs Gators By Huge Score In Athens ...
Here we report the development of an amphibious artificial vision system with a panoramic visual field inspired by the ... and bioinspired electronic eyes are restricted in their maximum field of view to a hemispherical field of view (around 180°). ... The comb-shaped image sensor arrays on the spherical substrate exhibit an extremely wide field of view covering almost the ... Biological visual systems have inspired the development of various artificial visual systems including those based on human ...
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 ...
What glaucoma patients actually see might differ from what visual field tests show; early glaucoma can be missed if patient ... he prefers that patient-reported symptoms be correlated with the traditional measures of visual acuity and visual field before ... The researchers assessed visual agreement by comparing the laterality of the indicated field loss and the laterality of patient ... "Everybody assumes that the visual field gets lost and it becomes narrower and narrower" with glaucoma, said Kouros Nouri- ...
Thirteen patients with transient or permanent homonymous visual field defects experienced formed hallucinations localized to ... the affected part of the visual field. The lesion was occipital in 8 instances (infarction 7, porencephalic cyst 1), ... permanent homonymous visual field defects experienced formed hallucinations localized to the affected part of the visual field ... Simple formed hallucinations confined to the area of a specific visual field defect Brain. 1976 Dec;99(4):719-34. doi: 10.1093/ ...
... EasyChair Preprint no. 1066. 6 pages• ... The site of intervention is the visual field in a techno-logically augmented society. All the three machines have both internal ... Hyper-commoditized vision - monetized vision that meditates on the omnipresent advertisement targeted all over our visual field ... Exploring the States of the Visual Field in the Age of Extreme Augmentation}, howpublished = {EasyChair Preprint no. 1066}, ...
Learn how the visual field test is performed. Abnormal results could indicate glaucoma, optic nerve glioma, and more. ... Visual field testing is a way to measure your entire visual field, or how much you can see to each side while focusing your ... Measuring Your Visual Field There are different ways to conduct a visual field examination. The most common way to measure the ... When a visual field deficit is discovered with the finger counting method or if the physician suspects visual field changes, a ... has one of the largest selections of new, used, and refurbished Visual Field Analyzer equipment on the market. ... Find Visual Field Analyzer Equipment For Sale, or Wanted from the worlds largest medical equipment marketplace. ... Used and New Visual Field Analyzer Parts Listings. Ad Statistics. Times Displayed: 531696. Times Visited: 7713 ... ZEISS/HUMPHREY FDT/Matrix Visual Field Analyzer Parts For Sale Part Number: Patient Response Button New Patient Response Button ...
Visuel field test as a routine during ophtalmological examination of EPI villages  ...
John Fields. Senior Director. This email address is being protected from spambots. You need JavaScript enabled to view it.. ... John accepted the position of first Curator for the Abroms Engel Institute for the Visual Arts in 2014. Since then, he has ... John was appointed Interim Director of the UAB Visual Arts Gallery in 2011. During his tenure, John produced 18 exhibitions for ...
Visual field testing is a crucial component of the neurologic, and more specifically the ophthalmologic, examination. A lesion ... encoded search term (Visual Field Testing) and Visual Field Testing What to Read Next on Medscape ... the visual field is plotted in degrees of arc. Several devices exist to aid in the plotting of the visual field. With all ... This is repeated throughout all areas of the visual field until a complete visual profile can be created. Kinetic perimetry ...
Visual field deficits in conventional anterior temporal lobectomy versus amygdalohippocampectomy. R. A. Egan, W. T. Shults, N. ... Visual field deficits in conventional anterior temporal lobectomy versus amygdalohippocampectomy. R. A. Egan, W. T. Shults, N. ... Objective: To evaluate and identify the incidence of visual field defects (VFD) after anterior temporal lobectomy (ATL) versus ... Postoperative kinetic field testing using the I4e isopter on a Goldmann perimeter was performed 30 days or more after surgery. ...
The new virtual reality headsets are changing the way visual field testing is performed on patients, Mitch Ibach, OD, FAAO, ...
... a visual field acuity test is a painless test that maps central vision as well as peripheral (side) vision. It is used to ... Visual field test. Overview. A visual field acuity test is a painless test that determines how well a person can see. The test ... How does a visual field test work?. During a visual field acuity test, also called a perimetry test, you will respond to a ... What does a visual field test show?. The visual field test produces a computer printout of the light thresholds that the ...
Client: Still Fields Brewery Designer: Mike Withers, Lisa Stuve Photographer: Jaclyn Roth Printer: Bleed Printing ... Still Fields Brewery. Beverages-Alcohol Entire Package - Series. 2022. Mike Withers and Lisa Stuve, Toronto, ON t: 778-986-7466 ... Still Fields is a brewery with a focus on traditional oak-barrel brewing and craft, while experimenting with unexpected ... The Applied Arts Awards celebrate innovative creativity, and capture the current visual arts landscape in Canada and beyond. ...
CSIs in the central visual field however have limited applicability as they have only been described using visual field test ... In this study, CSIs were determined within the central 20° visual field using the 10-2 test grid paradigm of the Humphrey Field ... Contrast Sensitivity Isocontours Of The Central Visual Field. We have a new manuscript out in Nature Scientific Reports, ... The number of CSIs detected in the central 20° visual field was greater than previously reported with low spatial sampling and ...
Visual field test. Central and peripheral vision is tested by using visual field tests. Changes may indicate eye diseases, such ...
This idea has received support from a recent study which found that, when neural activation in the frontal eye fields was ... boosted by magnetic stimulation, the observers detection performance on a visual task improved. ... This idea has received support from a recent study which found that, when neural activation in the frontal eye fields was ... boosted by magnetic stimulation, the observers detection performance on a visual task improved. ...
... visual field defects, basic concepts of visual field testing, visual field testing methods including automated perimetry, ... monitoring automated visual field testing for reliability, and advanced concepts in visual field testing. ... This course on visual field testing discusses the visual pathways, ... This course on visual field testing discusses the visual pathways, visual field defects, basic concepts of visual field testing ...
... rapid visual event detection (e.g. a looming motion expected to correspond to an approaching target), thus a-priori ... assumptions about the visual surroundings. 2) The algorithmic capability of dual kinds of connectivity of the thalamic neurons ... Its cortical and collicular maps are implemented with Dynamic Neural Fields (DNF) (7). We study how from such local operators ... emulating the thalamo-cortico-collicular visual system of mammals. This model integrates knowledge about the properties of both ...
Changes in Visual Cortical Connectivity Following Central Visual Field Loss * Connectomic Imaging in Familial & Sporadic ... Age-Dependent Cortical Thinning of Peripheral Visual Field Representations in Primary Visual Cortex.. Joseph C Griffis, Wesley ... visual only, or simultaneous auditory and visual). We found that patterns of trial-independent activity in early visual areas ( ... We found that when the visual stimulus was attended, background connectivity between V1 and the left frontal eye fields (FEF), ...
Dispersant Application Monitoring: Tier I Visual Observation Field Guide A guide to the indicators and factors influencing the ... Dispersant Application Monitoring: Tier I Visual ObservationField Guide This short field guide is intended to be used by anyone ... Additionally guidance is given on the visual observations that indicate whether dispersant is effective at dispersing the ... to combat oil spills at sea to provide a qualitative assessment of the efficacy of dispersant operations using visual ...
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... (1996 ... The afferent receptive fields develop a sparse coding of the visual input, and the recurrent lateral interactions eliminate ... Self-Organization and Functional Role of Lateral Connections and Multisize Receptive Fields in the Primary Visual Cortex}, ... Cells in the visual cortex are selective not only to ocular dominance and orientation of the input, but also to its size and ...
Measuring sensitivity to social and non-social information across the visual field ... Measuring sensitivity to social and non-social information across the visual field. In: Budapest CEU Conference on Cognitive ...
Visual Field Outcomes in Pediatric Patients with NF1-associated Optic Pathway Gliomas ... Visual Field Outcomes in Pediatric Patients with NF1-associated Optic Pathway Gliomas Administered By * Pediatrics, Hematology- ...
Visual field classification system and grading. In order to include visual field defect types associated with high myopia, new ... Of the 1434 visual fields, 540 were removed due to unreliability (167) or repeats (373), leaving 894 unique visual fields used ... Visual field examination. A total of 487 subjects underwent bilateral standard automatic perimetry (Zeiss Humphrey Visual Field ... The high myopes with arcuate-like visual fields will be followed to watch for visual field progression over the next 10 years. ...
Third International Visual Field Symposium Tokyo, May 3-6, 1978 (Documenta Ophthalmologica Proceedings #19) (Paperback) ... 2. Visual field defects due to tumors of the sellar region. Glaucoma. 1. The earliest visual field defects in glaucoma. 2. The ... ERIK L. GREVE The 3rd International Visual Field Symposium was held on the 4th till the 6th of May 1978 in Tokyo for the ... Third International Visual Field Symposium Tokyo, May 3-6, 1978 (Documenta Ophthalmologica Proceedings #19) (Paperback). By E. ...
... that suggest that language influences color discrimination strongly in the right visual field but not in the left visual field ... Further evidence that Whorfian effects are stronger in the right visual field than the left ... although we find that Whorfian effects on color are stronger for stimuli in the right visual field than in the LVF, we find ... Further evidence that Whorfian effects are stronger in the right visual field than the left. Proceedings of the National ...
Micro Medical Devices is dedicated to producing high-quality visual field analyzing handheld devices to help eye doctors ... the G2 adds the capability to perform a range of visual screening tests in addition to its visual field capability. ... "With the number of functionalities in this new device that could really help us a lot, were taking visual field testing to a ... Aware of how much of a bottleneck traditional Visual Field Analyzers can be to the ongoing development and growth of the ...
  • Thirteen patients with transient or permanent homonymous visual field defects experienced formed hallucinations localized to the affected part of the visual field. (
  • To evaluate and identify the incidence of visual field defects (VFD) after anterior temporal lobectomy (ATL) versus amygdalohippocampectomy (AH). (
  • Visual field defects can vary depending where along the visual pathway a lesion (red triangle) is located. (
  • This course on visual field testing discusses the visual pathways, visual field defects, basic concepts of visual field testing, visual field testing methods including automated perimetry, monitoring automated visual field testing for reliability, and advanced concepts in visual field testing. (
  • Purpose To describe a new combined myopia and glaucoma visual field classification system in order to report the visual field defects in a population of mostly young Chinese high myopes aged 7-70 years. (
  • Methods A total of 1434 visual fields (including confirmatory repeats of abnormal defects) from 487 high myopes (sphere ≤−6.0 D) were analysed from the prospective Zhongshan Ophthalmic Center-Brien Holden Vision Institute (ZOC-BHVI) High Myopia Registry Study. (
  • These subjects are being followed prospectively to assess which ones will progress to differentiate myopic from glaucomatous field defects. (
  • 2) Although the diagnosis of glaucoma relies upon characteristic optic nerve cupping with associated progressive visual field loss, myopic degeneration can also cause similar glaucomatous-like visual field defects. (
  • 1. Funduscopic correlates of visual field defects. (
  • 2. Visual field defects due to tumors of the sellar region. (
  • 1. The earliest visual field defects in glaucoma. (
  • 2. The reversibility of glaucomatous visual field defects. (
  • comprehension and/ or attention difficulties and visual field defects (VFD) [ 1 ]. (
  • Conducting a visual field test is called perimetry. (
  • When a visual field deficit is discovered with the finger counting method or if the physician suspects visual field changes, a more formal method will be used called standard automated perimetry (SAP). (
  • During a visual field acuity test, also called a perimetry test, you will respond to a series of flashing lights while looking straight ahead. (
  • Perimetry is used to measure the peripheral and central visual fields of each eye in a more detailed and sophisticated manner. (
  • With the use of perimetry, the visual field is plotted in degrees of arc. (
  • With all perimetry devices, the testing involves the patient fixing their gaze on a central target, while stimuli, usually flashes of light, are presented throughout the central and peripheral visual fields. (
  • Static perimetry tests individual locations throughout the visual field. (
  • Results: Suboptimal perimetry field settings were reported in 37% of VF studies. (
  • Perimetry field settings varied among patients and for some patients varied preoperatively versus postoperatively. (
  • 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. (
  • Moreover, computer training, used in border rehabilitation and based on having patients practise perimetry at home using a special software (Vision Restoration Therapy (VRT) by NOVAVISION), was widely discussed, since first studies reported its positive effect on the visual field in hemianopic patients, [ 9 ] whereas another research did not confirm these results. (
  • The area where vision is interpreted is called the primary visual cortex. (
  • Age-Dependent Cortical Thinning of Peripheral Visual Field Representations in Primary Visual Cortex. (
  • Primary visual cortex (V1) is considered to be the most basic cortical area in the visual processing hierarchy, and is topographically organized from posterior (central visual representation) to anterior (peripheral visual representation) along the calcarine sulcus. (
  • The Development of Receptive Field Tuning Properties in Mouse Binocular Primary Visual Cortex. (
  • The mouse primary visual cortex is a model system for understanding the relationship between cortical structure, function, and behavior (Seabrook et al. (
  • Visual fields in retinal disease. (
  • An important property of early visual cortices is their topographic organization-the cortical structure of early visual areas forms a topographic map of retinal inputs. (
  • 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 particular type of hallucination is considered as an irritative phenomenon of the visual association cortex which can be symptomatic of a parieto-occipital lesion and does not necessarily implicate the temporal lobes. (
  • It is suggested that the visual association cortex amy be responsible for the organization of visual percepts into broad categories of which people, animals and objects are representative. (
  • The occurrence of such hallucinations with a visual field defect suggests that the cells of the association cortex are more likely to discharge spontaneously once they are deprived of their normal afferent inflow from the calcarine cortex. (
  • We propose to examine connections between the early visual cortex and frontal and parietal brain networks, which have the potential to be more plastic. (
  • Cells in the visual cortex are selective not only to ocular dominance and orientation of the input, but also to its size and spatial frequency. (
  • Together with our previous work on ocular dominance and orientation selectivity, these results suggest that a single Hebbian self-organizing process can give rise to all the major receptive field properties in the visual cortex, and also to structured patterns of lateral interactions, some of which have been verified experimentally and others predicted by the model. (
  • The model also suggests a functional role for the self-organized structures: The afferent receptive fields develop a sparse coding of the visual input, and the recurrent lateral interactions eliminate redundancies in cortical activity patterns, allowing the cortex to efficiently process massive amounts of visual information. (
  • Early deafness is responsible for processing the visual stimuli in auditory cortex due to plasticity of neuronal cells in the auditory cortex. (
  • The FACADE model, and its laminar cortical realization and extension in the 3D LAMINART model, have explained, simulated, and predicted many perceptual and neurobiological data about how the visual cortex carries out 3D vision and figure-ground perception, and how these cortical mechanisms enable 2D pictures to generate 3D percepts of occluding and occluded objects. (
  • This is to ensure that there is no other cause for visual field loss, visual impairment, or other ocular disease. (
  • A minimal visual field impairment was detected in some cases and most of patients had no particular change of basal data. (
  • Visual field constriction as a cause of blindness or visual impairment. (
  • The family will be asked about the onset of the visual impairment, eye surgeries and dates, current treatments and medications and about the students general health. (
  • The specialist may be able to better explain the visual impairment to the family. (
  • In this study, CSIs were determined within the central 20° visual field using the 10-2 test grid paradigm of the Humphrey Field Analyzer which has a high 2° sampling frequency. (
  • Able to run threshold, neuro, and ptosis tests in perfect alignment with the Humphrey Field Analyzer and generate familiar, easy to read reports, this innovation is a must have for the modern practice. (
  • An automated visual field analyzer is an automated tool that is very frequently employed by Optometrists, orthoptists, and ophthalmologists to measure the human visual field, especially to identify monocular visual fields. (
  • The Swedish Interactive Thresholding Algorithm, or SITA, which is now used by the analyzer, enables the quickest and most precise visual field assessment to date. (
  • Due to a number of efforts and initiatives being taken by several market players operating in the automated visual field analyzer market, the turnaround time of these analyzers has been reduced significantly. (
  • Despite a number of benefits of an automated visual field analyzer, there is a major drawback of this technology. (
  • The majority of studies (54%) used the Humphrey Field Analyzer. (
  • Inclusion criteria consisted of paired SPECTRALIS® macular OCT volume scans (61 B-scans) and Humphrey Field Analyzer (HFA) 24-2 SITA Standard VF exams. (
  • The visual reaction time is measured by response analyzer and the field of vision is tested by Priestly-Smith's perimeter in the deaf children and compared with the normal hearing children in the age group of 8-16 years. (
  • Your responses help determine if you have a defect in your visual field. (
  • Visual neglect, a defect in central processing, (usually the right parietal lobe) may not be apparent in conventional confrontation testing. (
  • Visual field defect (VFD) is one of the most common impairments that can occur after the brain damage. (
  • Prosopagnosia is the inability to recognise familiar faces despite having normal visual acuity and visual fields. (
  • High Symmetry of Visual Acuity and Visual Fields in RPGR-Linked Retinitis Pigmentosa. (
  • The normal visual field reaches 180º in the horizontal plane (160º for monocular vision) and 135º in the vertical plane. (
  • History of present illness should describe loss of vision in terms of onset, duration, progression, and location (whether it is monocular or binocular and whether it involves the entire visual field or a specific part and which part). (
  • or You have a limitation in the field of vision of your better eye, so that: You have a contraction of peripheral visual fields to 10 degrees from the point of fixation, or The widest diameter of your visual field subtends an angle no greater than 20 degrees, or You have a contraction of peripheral visual fields to 20 percent or less visual field efficiency. (
  • The specialist will assess the central and peripheral visual fields. (
  • Visual field testing in glaucoma. (
  • March 5, 2012 (New York, New York) - A study designed to determine what glaucoma patients actually see during various stages of glaucoma progression suggests that the early signs of glaucoma - according to the patient - differ from the suggested results of a visual field test. (
  • The classic understanding of glaucoma is that you end up with a little tubular field," explained George L. Spaeth, MD, from the Wills Eye Institute, Philadelphia, Pennsylvania. (
  • We wanted to disengage reported symptoms from the influence of other things that can cause glaucoma-like visual symptoms, such as cataract," said Dr. Spaeth. (
  • The field loss starts on the nasal side, not on the peripheral side, yet we're constantly telling our patients, 'you will lose peripheral vision in glaucoma. (
  • If someone is telling you they need more light, regardless of what the field test is telling you, their glaucoma may very well be getting worse. (
  • Everybody assumes that the visual field gets lost and it becomes narrower and narrower" with glaucoma, said Kouros Nouri-Mahdavi, MD, assistant professor of ophthalmology at the Jules Stein Eye Institute, University of California at Los Angeles. (
  • Conclusions A proposed combined visual field classification for high myopia and glaucoma demonstrates acceptable intergrader agreement. (
  • 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. (
  • A visual field test is an examination that reveals central and peripheral vision problems that can be caused by a variety of medical disorders such as glaucoma, stroke, pituitary illness, brain tumours, or other neurological abnormalities such as macular degeneration. (
  • Glaucoma in general is more than a single disease entity: it is a group of conditions characterized by progressive optic nerve degeneration (detectable by pathological cupping of the optic disc) and loss of visual function, ultimately resulting in total blindness. (
  • For the 92 eyes assessed (46 patients, both eyes), there was symptom/field agreement for 58 eyes, disagreement for 22, and an uncertain assessment for 12 eyes. (
  • Some patients will have a completely normal test, while others will show a visual field loss that is in one or both eyes). (
  • Visual field testing may prove to be difficult as a simple bedside test in children and obtunded patients. (
  • In obtunded patients, the examiner should assess the patient's blink response to a visual threat, such as the examiner's finger or any small object that is quickly moved toward the patient's eye in all regions of the visual field. (
  • Active Eye tracking follows the gaze of patients during a visual field test, allowing for more precision in this important test. (
  • The VF2000 Focus performs visual threshold tests, ptosis tests, neurological tests, and the Esterman test in a virtual reality setting, making it a perfect fit for practices with space constraints and patients who have difficulty with traditional methods. (
  • Methods that quantify the rate of visual field progression seem to be the most appropriate for guiding subsequent medical actions in individual patients. (
  • Visual field testing is non-invasive, painless and doesn't require patients to have their eyes dilated. (
  • The aim of the presented case is to demonstrate that optometric vision therapy (OVT) in open space, commonly used in patients with binocular vision disorders, may be an alternative and efficient treatment of VFD, since it focuses on the integration of sensory and motor functions with the strong engagement of visual attention. (
  • However, it is observed that the influence of the implemented rehabilitation on visual field border often differs considerably between patients [ 8 ]. (
  • Visual field was performed in thirteen patients affected by cerebral neoplasms after treatment with intra-arterial Carboplatin and Etoposide therapy, in order to evaluate a possible toxic effect. (
  • 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. (
  • Investigative Ophthalmology & Visual Science June 2022, Vol.63, 2016 - A0457. (
  • Investigative ophthalmology & visual science 2022 2 63 (2): 13. (
  • A visual field test can also tell the ophthalmologist and surgeon whether a lesion is located in front of, on, or behind the optic chiasm. (
  • 2. The relation between the position of a lesion in the fundus and in the visual field. (
  • As a result, it offers details on where any disease activates or lesion may be located along the visual pathway. (
  • If there is unilateral ______ blindness or enucleation, visual fields in the remaining eye are scored. (
  • Dr. Spaeth suggested that part of the problem is that when binocular testing is impaired, the better eye will completely mask the visual loss. (
  • Magnified visual examination of the cervix using a low-power stereoscopic binocular field microscope with a powerful light source. (
  • A large number of methods have been developed for assessing glaucomatous visual field progression, but their properties have not yet been systematically evaluated. (
  • Although there is no gold standard to assess glaucomatous visual field progression, we found evidence on validity for 48 different methods. (
  • The examiner presents stimuli in the right and left visual fields simultaneously. (
  • Our results differ in one respect: although we find that Whorfian effects on color are stronger for stimuli in the right visual field than in the LVF, we find that there are significant category effects in the LVF as well. (
  • The deaf depend on the visual stimuli to judge three dimensional objects as well as to moving stimuli in the periphery. (
  • Following the visual field test, your eyes may be dilated to examine the retina, macula, and optic nerve. (
  • Red-dot card test of the paracentral field as a screening test for optic nerve disease in onchocerciasis. (
  • This work suggests detection of CSIs within the central 20° is dependent on sampling strategy and stimulus size and normative distribution limits of CSIs can indicate significant functional deficits in diseases affecting the central visual field such as AMD. (
  • Moreover, VFD is the one of the most common visual deficits in ABI [ 4 ]. (
  • Acquired brain injury (ABI), beyond the physical, cognitive and/or psychological impairments, strongly affects visual functions. (
  • These tests can also be used to assist in diagnosing the disease process in some visual impairments. (
  • This "lobectomy" surgery removed his entire occipital lobe, which carries out visual processing, and most of his temporal lobe, which processes visual and auditory information. (
  • Remarkably, they found that his intellect, visual perception, and face and object recognition skills were all normal for his age. (
  • Confrontation visual field exam. (
  • The most common way to measure the four quadrants of a visual field is to perform confrontation neurologic visual fields. (
  • Both optometrists and ophthalmologists perform confrontation visual fields with this method during a comprehensive eye examination. (
  • Visual fields (upper and lower quadrants) are tested by 0 = No visual loss confrontation, using finger counting or visual threat as appropriate. (
  • They gave all subjects a comprehensive ocular examination, including field testing, and then asked them to respond to an oral questionnaire about visual symptoms. (
  • There are different ways to conduct a visual field examination. (
  • The Clinical Low Vision Evaluation differs from the medical examination from an optometrist or ophthalmologist in that it provides functional, usable information about the visual abilities of an individual who has low vision. (
  • a subsequent physical examination included visual inspection and bimanual palpation of the face for the presence of specific signs. (
  • Two independent graders reviewed the first 150 of 1434 fields for initial grading calibration and the remaining 1284 fields were used to assess intergrader agreement. (
  • Tools for scholars and writers to help discover and assess the literature of the field. (
  • The specialist will assess the general condition of the structures of the eyes in order to determine the nature and extent of the visual diagnosis. (
  • The specialist will assess the students visual acuities both with and without correction. (
  • There are a variety of tools to assess the students fields. (
  • Tangent screen or Goldmann field exam. (
  • Postoperative kinetic field testing using the I4e isopter on a Goldmann perimeter was performed 30 days or more after surgery. (
  • Contrast sensitivity isocontours (CSIs) may reduce test variability in SAP by identifying regions of the visual field with statistically similar patterns of change that can be analysed collectively and allow a point (disease)-to-CSI (normal) comparison in disease assessment as opposed to a point (disease)-to-point (normal) comparison. (
  • This short field guide is intended to be used by anyone using dispersants to combat oil spills at sea to provide a qualitative assessment of the efficacy of dispersant operations using visual observations. (
  • Effects of acutely lowering intraocular pressure on the results of multifocal visual evoked potential testing. (
  • The simulations reported in this paper show how size selectivity could develop through Hebbian self-organization, and how receptive fields of different sizes could organize into columns like those for orientation and ocular dominance. (
  • however, if the examiner presents a stimulus in the right and left temporal region simultaneously, the patient with neglect will only be able to identify the stimulus in the right temporal field. (
  • The number of CSIs detected in the central 20° visual field was greater than previously reported with low spatial sampling and stimulus size dependent: 6 CSIs for GI, 4 CSIs for GII and GIII, and 3 CSIs for GIV and GV. (
  • This evaluates the retina's capacity to find a stimulus at particular locations within the visual field. (
  • This idea has received support from a recent study which found that, when neural activation in the frontal eye fields was boosted by magnetic stimulation, the observers' detection performance on a visual task improved. (
  • Such detection is based on two functional interacting ingredients: 1) The capability of the retina to provide coarse, rapid visual event detection (e.g. a looming motion expected to correspond to an approaching target), thus a-priori "assumptions" about the visual surroundings. (
  • 7 ] suggested that both techniques bring different benefits, since the former improves visual signal detection, whereas the latter enhances their processing. (
  • From the point of view of product use, machine vision is not only used as a single product in the field of quality detection, but also widely installed in industrial robots, CNC machine tools and other industrial automation products. (
  • It can also be used to monitor the progression of previously known visual field loss. (
  • Impact of annual dosing with ivermectin on progression of onchocercal visual field loss. (
  • This article describes the test that measures your visual field. (
  • Dr. Spaeth's team analyzed data using the Cochran-Armitage trend test to determine if there was an association between MD category and visual symptoms. (
  • Have you ever been asked to take a computerized visual field test? (
  • Although many people mistake it as simply a peripheral vision test, a visual field test is actually designed to measure the overall field of vision as it is interpreted by the brain in four neurological quadrants. (
  • Results of a visual field test can sometimes help physicians make a diagnosis. (
  • This test is able to conduct several different types of field tests in a standardized fashion. (
  • A visual field acuity test is a painless test that determines how well a person can see. (
  • How does a visual field test work? (
  • What does a visual field test show? (
  • The visual field test produces a computer printout of the light thresholds that the patient's eyes were able to perceive and process (Fig. 2). (
  • Visual field test of a patient with a meningioma shows vision loss (black areas) in half of the right eye, called hemaniopia. (
  • An ophthalmologist, a doctor who specializes in diseases and surgery of the eye, eyelids, and areas surrounding the eyes, performs the visual field test. (
  • Visual field results are interpreted to establish artifact from disease to account for an abnormal test. (
  • CSIs in the central visual field however have limited applicability as they have only been described using visual field test patterns with low, 6° spatial sampling. (
  • We will test our central hypothesis by identifying how the following characteristics of early visual areas change after central vision loss: 1) functional connectivity to fronto-parietal control regions, (2) structural measures of white matter integrity, (3) cortical thickness. (
  • For example, the result of a test conducted with the automated field tester can be very easily hampered by incorrect placement of the head. (
  • Next, students from both groups were given the Children's Embedded Figures Test (CEFT) to determine field independence/dependence. (
  • With examples of routine in-ground stake tests differences are shown in the performance of wood preservatives at the BAM test fields Lehre and Horstwalde and in the BAM fungus cellar. (
  • At comparable decrease rates of the MOE the visible signs of fungal attack developed slower at the test fields than in the fungus cellar. (
  • This study investigated the relationship between visual selective attention and the cognitive style of field independence/dependence in 20 kindergarten children. (
  • The students were given a visual selective attention task to determine which students were in the visual selective attention stage. (
  • those students who were in the visual selective attention stage and those who were not. (
  • This asymmetry is likely related to the contralateral projection of visual fields to cerebral hemispheres and the specialization of the left hemisphere for language. (
  • The nucleus contains a single orderly map of the contralateral visual hemifield. (
  • This eye exam will show whether you have a loss of vision anywhere in your visual field. (
  • The researchers assessed visual agreement by comparing the laterality of the indicated field loss and the laterality of patient-reported symptoms. (
  • If a patient with a verified left-sided field loss reported a loss of vision on the left side of the eye, this was assessed as "field and symptom agreement. (
  • The converse - left-sided symptoms for an eye with right-sided field loss - was recorded as a disagreement between field and symptom. (
  • In 20% of cases, the cause of the loss of side vision was not loss of field," Dr. Spaeth said. (
  • Little is known about the incidence of VFD after AH and this surgical method offers the possibility of a seizure-free survival without visual loss. (
  • Your responses will help the doctor determine whether you have a visual field loss. (
  • The area of vision loss gives clues as to where in the visual pathway a problem has occured. (
  • Visual field loss, also known as "visual field cut," can be partial or complete. (
  • People with visual field loss may have trouble seeing objects out of the corner(s) of their eyes, lose their place while reading, startle when people or objects move toward them, or bump into people and objects. (
  • The mechanisms underlying this visual plasticity are not known, but are of great clinical interest, because better understanding can lead to improved treatment strategies following vision loss. (
  • We will make use of the Human Connectome Project dataset and protocols to identify how the structure and connections of early visual areas are altered following loss of central vision due to macular degeneration. (
  • These aims are expected to yield information about how top-down connections to early visual areas contribute to plasticity after vision loss. (
  • The former aims at restoration some part of visual field, and the latter is directed to compensate the loss, by teaching more effective ways of using the remainder of the visual fields or through expansion of visual field by prisms [ 4 , 5 ]. (
  • One passive treatment - compensatory training, attempts to effectively manage the remaining visual field, thus adapting to the visual field loss. (
  • Another approach - restorative training aimed at restoration of visual field loss. (
  • The light flashes vary in intensity and appear in all quadrants of the visual field. (
  • Its cortical and collicular maps are implemented with Dynamic Neural Fields (DNF) (7). (
  • Our central hypothesis is that greater reliance on peripheral vision following MD leads visual cortical regions representing the periphery to become structurally and functionally more similar to those representing the macula, thus improving functional vision. (
  • Effects of aging on cortical thickness (CT) have been observed in many brain regions, including areas involved in basic perceptual functions such as processing visual inputs. (
  • 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. (
  • Visual field testing is a way to measure your entire visual field, or how much you can see to each side while focusing your eyes on a central point (peripheral vision). (
  • A moving target should start outside the usual 180 º visual field, then move slowly to a more central position until the patient confirms visualization of the target. (
  • We have a new manuscript out in Nature Scientific Reports, Contrast Sensitivity Isocontours Of The Central Visual Field . (
  • Central and peripheral vision is tested by using visual field tests. (
  • 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. (
  • Both central and peripheral vision are tested using visual field analysis. (
  • In a field situation, however, even skilled segment of the eye was examined using ophthalmologists find it difficult to diag- direct ophthalmoscope. (
  • It directs and aids in the diagnosis of the visual disorder affecting the patient. (
  • At that time, machine vision has been successfully used in industrial robots, automatic control, medical diagnosis, security monitoring and industrial testing and other fields. (
  • Equipped with an upgraded 4K display, the G2 adds the capability to perform a range of visual screening tests in addition to its visual field capability. (
  • Recent developments in the technology are leading to the development of various novel visual function tests. (
  • After treatment both visual search field expansion and a reduction of time needed for searching objects were reported [ 6 ]. (
  • Select up to three search categories and corresponding keywords using the fields to the right. (
  • The lateral connections in the network self-organize cooperatively and simultaneously with the receptive field sizes, and produce patterns of lateral connectivity that closely follow the receptive field organization. (
  • The projection of the visual field onto the dorsal lateral geniculate nucleus (LGN) of the ferret was mapped electrophysiologically. (
  • Zahs, KR & Stryker, MP 1985, ' The projection of the visual field onto the lateral geniculate nucleus of the ferret ', Journal of Comparative Neurology , vol. 241, no. 2, pp. 210-224. (
  • Stryker, Michael P. / The projection of the visual field onto the lateral geniculate nucleus of the ferret . (
  • Brand New Patient Response Button for Humphrey/Zeiss FDT 710, MATRIX 715 and Matrix 800 Visual Fields. (
  • Visual programming, with visual cues to define relationships, offers a graphical approach to programming, where preconfigured code blocks are utilized in place of textual lines of code to develop an application. (
  • Aware of how much of a bottleneck traditional Visual Field Analyzers can be to the ongoing development and growth of the practice, we developed the VF2000 with the everyday doctor in mind. (
  • These analyzers examine the patient's whole vertical and horizontal field of peripheral vision, looking for any probable vision problems or blind spots (scotomas). (
  • COVID-19 had a negative impact on the automated visual field analyzers market because of elements, like the delay of elective hospital procedures, including eye exams, and the infection risk, which has led to a decline in the number of individuals attending eye clinics. (
  • In the modern era, there is a number of advancements that are being introduced in automated field analyzers. (
  • The turnaround time for automated visual field analyzers has greatly decreased, and accuracy in visual field testing has increased in contrast to recent years. (
  • Automated visual field analyzers are highly prone to making errors due to a number of factors. (
  • Students opting for the creative practice route will produce a body of supervised practice-based work designed for exhibition, accompanied by a dissertation of up to 50,000 words intended to assist them in contextualising their work within the broader field of visual culture. (
  • Visual representations of leading scientific literature track the ground breaking papers in various scientific fields. (