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
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 ...
Loss of vision in right side of visual field, both eyes, five times, twice with speaking disorders. First time 18 months ago. Visual problem resolved in 10 minutes after aspirin, followed by verbal deficits for half an hour. CAT scan of brain two days later showed no problems Then on 16 of June this year, same: visual disturbance, right side of both eyes, resolved after aspirin in 10 minutes. Drove self to hospital in 20 minutes. At intake I could not speak clearly. Could not pronounce
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 ...
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 ...
T. Lindeberg (2013a). "Invariance of visual operations at the level of receptive fields". PLOS ONE. 8 (7): e66990:1-33. doi: ... doi:10.1016/B978-0-12-407701-0.00001-7. T. Lindeberg (2021). "Normative theory of visual receptive fields". Heliyon. 7 (1): ...
They also have an increased binocular vision and depth of visual field as a result of the cephafoil. The shape of the head was ... 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 ... have compared Moken and untrained European children and found that the underwater visual acuity of the Moken was twice that of ...
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 capacity of the horse[edit]. Visual field[edit]. The range of a horse's monocular vision, blind spots are in shaded ... A horse's visual field is lowered when it is asked to go "on the bit" with the head held perpendicular to the ground. This ... Visual acuity and sensitivity to motion[edit]. The horse has a "visual streak", or an area within the retina, linear in shape, ... The equine eye is the one of the largest of any land mammal.[1] Its visual abilities are directly related to the animal's ...
"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, and is spread out across four buildings: the exhibition hall at Block 43 Malan Road, ... 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 ...
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 ...
"Mechanisms Underlying Development of Visual Maps and Receptive Fields". Annual Review of Neuroscience. 31 (1): 479-509. doi: ... He is the recipient of the 2017 ARVO Cogan Award for making major contributions to the fields of vision science and efforts to ... A large amount of that work focused on the visual system, including the mechanisms that control light-mediated activation of ... After moving to Stanford in 2016, Huberman discovered and published the use of non-invasive methods such as visual stimulation ...
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 ...
... director of visual and miniature effects; Roy Field, optical visual effects supervisor; and David Lane, flying and second unit ... The visual effects unit, as well as several of the production staff, were Salkind stalwarts from the Superman films: Derek ...
... and typically affects the visual field more than visual acuity. Additionally, there is an increased risk of serous retinal ... Coloboma of optic nerve, is a rare defect of the optic nerve that causes moderate to severe visual field defects. Coloboma of ...
Visual perception Field dependence Corbett, J.; Enns, J. (2006). "Observer pitch and roll influence: The rod and frame illusion ... These findings suggest that the rod and frame illusion is processed in a type of hierarchy, where visual input is at the top, ... Past research has found that one reason people experience the rod and frame illusion is due to visual-vestibular interactions. ... Lipshits, M.; Bengoetxea, A.; Cheron, G.; McIntyre, J. (2005). "Two reference frames for visual perception in two gravity ...
... may cause visual field defects. Topiramate may decrease effectiveness of oestrogen-containing oral contraceptives. ... Discontinuation of topiramate may halt the progression of the ocular damage and may reverse the visual impairment. Preliminary ... Visual disturbance Vertigo Tinnitus Ear pain Dyspnoea Epistaxis Nasal congestion Rhinorrhoea Vomiting Constipation Abdominal ...
Rice is the major crop grown; the extensive paddy fields, around Sholavandan are a visual evidence. Bananas and coconuts are ...
Wurtz RH (1969). "Visual receptive fields of striate cortex neurons in awake monkeys". J Neurophysiol. 32 (5): 727-742. doi: ... He began studies on the visual system of awake in monkeys and made groundbreaking works on neurobiology of vision and eye ... His 1969 publications became classic papers on this technique of studying the physiology of the visual system, and now used by ... He is recognised for developing methods for studying the visual system in 'awake-behaving' primates (as opposed to those under ...
Receptive fields partially overlap, over-covering the entire visual field. Unit response can be approximated mathematically by ... In visual perception, humans focus on specific objects in a pattern. Humans can change focus from object to object without ... In S. C. Kremer and J. F. Kolen, editors, A Field Guide to Dynamical Recurrent Neural Networks. IEEE Press, 2001. Hochreiter, S ... Its unit connectivity pattern is inspired by the organization of the visual cortex. Units respond to stimuli in a restricted ...
Visual limit of the Hubble Deep Field. Reionization complete-the Universe becomes transparent again. Galaxy evolution continues ... 800 million years: Farthest extent of Hubble Ultra Deep Field. Formation of SDSS J102915+172927: unusual population II star ... so matter particles can acquire mass and interact with the Higgs Field. The temperature is still too high for quarks to ...
Eriksen CW, St James JD (October 1986). "Visual attention within and around the field of focal attention: a zoom lens model". ... The current view is that visual covert attention is a mechanism for quickly scanning the field of view for interesting ... Tsal Y (August 1983). "Movements of attention across the visual field". Journal of Experimental Psychology. Human Perception ... role of attention Philosophy Self Split attention effect Vigilance Visual search Working memory Visual spatial attention Visual ...
The most-noted visual is the long take of a bird soaring over the Baliem Valley that is the film's establishing shot. Reviewers ... MacDougall, David (1995). "The Subjective Voice in Ethnographic Film". In Devereaux, Leslie; Hillman, Roger (eds.). Fields of ... Anonymous (1965). "Audio Visual News". The Clearing House. 40 (1): 63-64 - via JSTOR. Jarvie, I. C. (1983). "The Problem of the ... its cultivated fields, and the fighting ground. A voiceover describes the great race between a bird and a snake which was to ...
... then that person is said to be dependent on the visual field. This person will be categorized as field-dependent. On the other ... apparently, women and men have different 'field dependence'. Short biography in Spanish The Model of field-dependency and field ... For the participant to be able to do this, he/she has to ignore cues in the visual field. If the participant adjusts the rod so ... Field-independent people seem to rely on their own sensations instead of the perception of the field, to make a judgment. The ...
"Receptive fields, binocular interaction and functional architecture in the cat's visual cortex". J. Physiol. 160 (1): 106-54. ... Olshausen, Bruno A.; Field, David J. (1997-12-01). "Sparse coding with an overcomplete basis set: A strategy employed by V1?". ... The early historical roots of the field can be traced to the work of people such as Louis Lapicque, Hodgkin & Huxley, Hubel & ... In some cases the complex interactions between inhibitory and excitatory neurons can be simplified using mean field theory, ...
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 relatively new neurofeedback technique within the field of neurotherapy. Neurofeedback, a ... which then calculates the ratio of red to infrared light and translates it into a visual signal of corresponding to oxygenation ...
Advances in the fields of molecular biology and genetics, as well as the use of animal models have been of great importance in ... When the ICP is elevated the following symptomes may occur: vomiting, visual disturbance, bulging of the anterior fontanel, ... Neurobehavioural impairment includes problems with attention and planning, processing speed, visual spatial skills, language, ... craniosynostosis results in increased intracranial pressure leading possibly to visual impairment, sleeping impairment, eating ...
The Yamadas and Chi finally leave the ranch, but then stop at a sunflower field and decide to take a picture. But then Chi ...
Topography and extent of visual-field representation in the superior colliculus of the megachiropteran Pteropus. „Visual ... Does the visual system of the flying fox resemble that of primates? The distribution of calcium-binding proteins in the primary ... visual pathway of Pteropus poliocephalus. „Journal of Comparative Neurology". 417 (1), s. 73-87, 2000. DOI: ,73::AID-CNE6,3.0. ...
Although there exist a few visual formulas to construct some of these ligatures, many of them have to be learned by rote. ... Language articles with unsupported infobox fields. *Articles with hAudio microformats. *Articles with DMOZ links ... but this intermediate expulsion of the inherent vowel is not indicated in any visual manner on the basic consonant sign ম [mɔ]. ...
"Arakawa deals with the visual field as discourse, modal systems that constitute the world rather than being constituted by it." ...
The Visual Food Encyclopedia. Québec Amerique. 1996. ISBN 9782764408988. .. *^ Davidson, Alan (2006). The Oxford Companion to ... Kaufman, Kenn (2005). Kaufman Field Guide to Birds of North America. Houghton Mifflin Harcourt. ISBN 978-0618574230. .. ... Feinstein, Julie (2011). Field Guide to Urban Wildlife. Stackpole Books. p. 130. ISBN 9780811705851. .. ... O'Neill, Michael J. (February 1973). Field & Stream. 77. Columbia Broadcasting System Publications. p. 108.. ...
Instead, it provides a visual representation of the Pure Land texts, and is used as a teaching aid.[citation needed] ... The whole paddy field, locally known as Bihu Loukon, is now protected and announced as historical monument and site by the ... The mandala can be shown to represent in visual form the core essence of the Vajrayana teachings. The mind is "a microcosm ... Located in the paddy field in the west of Imphal, the capital of Manipur, the Maklang geoglyph is perhaps the world's largest ...
P., Apps (2000). Wild Ways : Field Guide to the Behaviour of Southern African Mammals (2nd ed.). Cape Town: Struik. p. 146. ... They are fast runners, and communicate using a variety of visual and vocal communications. The primary breeding season for the ... Stuart, C.; Stuart, T. (2001). Field guide to mammals of southern Africa (3rd ed.). Cape Town: Struik. p. 202. ISBN 186-8725- ... Hilton-Barber, B.; Berger, L. R. (2004). Field Guide to the Cradle of Humankind : Sterkfontein, Swartkrans, Kromdraai & ...
As an emerging field, its definition and limits are the subject of ongoing debate. John Hall's lecture Thirteen Ways of Talking ... visual art, sound art, time-based media, installation, electronic literature, bookworks, and performance art.[1] ... The course was written, and the field developed, by a number of self-described Performance Writers and academics including John ... At the symposium launching the field, Performance Writing was described by Caroline Bergvall as exploring "relationships ...
Closest to the visual field (and farthest from the brain) is the axon terminal, which releases a neurotransmitter called ... Photoreceptors do not signal color; they only signal the presence of light in the visual field. ... will affect it and signal that light is in the visual field. This system may have less noise relative to sensory transduction ... each contributing information used by the visual system to form a representation of the visual world, sight. The rods are ...
Interdisciplinary fields[edit]. Some interdisciplinary sub-specialties of medicine include: *Aerospace medicine deals with ... and visual arts) and their application to medical education and practice. ... Related non-medical fields include psychotherapy and clinical psychology.. *Preventive medicine is the branch of medicine ... Many other health science fields, e.g. dietetics. Education and legal controls[edit]. Main articles: Medical education and ...
by itself for visual indentation).. However, a huge pile of drama has erupted at WT:MOSMATH#Indenting for no explicable reason ... While specialized publications in a field, such as academic journals, are excellent sources for facts, they are not always the ... the Manual of Style incorporates a substantial number of practices from technical standards and field-specific academic style ...
... es emit on the electromagnetic spectrum, with sferics and E-field effects detected.[45][47][48] There are observed ... Rotating wall clouds may be a visual manifestation of a low-level mesocyclone. Barring a low-level boundary, tornadogenesis is ... "Advanced Spotters' Field Guide" (PDF). National Oceanic and Atmospheric Administration. 2003-01-03. Retrieved 2009-12-13.. ... Research programs, including field projects such as the VORTEX projects (Verification of the Origins of Rotation in Tornadoes ...
"Across the Field", Ohio State's fight song, and "Buckeye Battle Cry" are commonly played and sung at athletic events, as well ... The center was founded to encompass all aspects of visual and performing arts with a focus on new commissions and artist ... track and field), John Havlicek, Jerry Lucas, Bobby Knight, and Larry Siegfried (basketball), 2010 Olympics silver medalist ... Larry Snyder in track and field, and Mike Peppe in swimming and diving. Hall of fame players, in pro-football, include Sid ...
Needham, T (2007). Visual Complex Analysis. New York: Oxford University Press. pp. 140-141. ISBN 978-0-19-853446-4. .. ... The problem of counting the number of solutions to different types of Apollonius' problem belongs to the field of enumerative ... which arise in disparate fields such as the error-correcting codes used on DVDs and the design of pharmaceuticals that bind in ... The Apollonian gasket also has deep connections to other fields of mathematics; for example, it is the limit set of Kleinian ...
"Visual Elements: Group 1 - The Alkali Metals". Visual Elements. Royal Society of Chemistry. Archived from the original on 5 ... which may have significant impacts on their interior magnetic fields.[169][170] It has been estimated that the transition from ...
Computer graphics is a sub-field of computer science which studies methods for digitally synthesizing and manipulating visual ... Computer graphics is often differentiated from the field of visualization, although the two fields have many similarities. ... Sub-field of computer science. This article is about the scientific discipline of computer graphics. For a broader overview, ... Out-of-core mesh processing - another recent field which focuses on mesh datasets that do not fit in main memory. ...
A bilateral temporal visual field defect (due to compression of the optic chiasm) or dilation of the pupil, and the occurrence ... visual field impairment, impaired sense of smell, impaired hearing, facial paralysis, double vision, or more severe symptoms ... "IARC classifies radiofrequency electromagnetic fields as possibly carcinogenic to humans" (PDF). World Health Organization ... and poor spatial and visual perception.[citation needed] ...
Similarly, the magnetic field creates a disturbance proportional to the magnetic susceptibility.) As the electromagnetic fields ... For optics in the visual range, the amount of dispersion of a lens material is often quantified by the Abbe number:[29] ... Since intensity is proportional to the square of the electric field, it will depend on the depth into the material as exp(−4πκz ... That κ corresponds to attenuation can be seen by inserting this refractive index into the expression for electric field of a ...
2000). Cetacean Societies: Field Studies of Dolphins and Whales. University of Chicago. p. 9. ISBN 0-226-50341-0.. ... Whales do, however, lack short wavelength sensitive visual pigments in their cone cells indicating a more limited capacity for ... Thomas, Jeanette A.; Kastelein, Ronald A. (1990). Sensory Abilities of Cetaceans: Laboratory and Field Evidence. 196. New York ... As well as this, the eyes of a whale are placed on the sides of its head, so their vision consists of two fields, rather than a ...
While holding a military position related to his field, he was given the task of creating a color blindness test. Ishihara ...
Mineral collecting is also a recreational study and collection hobby, with clubs and societies representing the field.[32][33] ... macroscopic visual properties (luster, color, streak, luminescence, diaphaneity); magnetic and electric properties; ... Biomineralogy is a cross-over field between mineralogy, paleontology and biology. It is the study of how plants and animals ... the field has made great advances in the understanding of the relationship between the atomic-scale structure of minerals and ...
The Visual F# tools from Microsoft include full IDE integration in Visual Studio. With the language service installed, Visual ... Values and record fields can also be labelled as mutable. . For example: // Define 'x' with initial value '1' let mutable x = 1 ... In addition, the Visual F# tools comes with a Visual Studio-hosted REPL interactive console that can be used to execute F# code ... یکی دیگر از مزیت‌های این زبان پشتیبانی کامل Visual Studio از این زبان می‌باشد به گونه ای که از نسخه ۲۰۰۸ به بعد در تمامی ...
Document-oriented databases such as IBM Notes allow multiple values in items (fields), do not require a schema, come with built ... LotusScript, a language resembling Visual Basic. The client supports a formula language as well as JavaScript. Software ... The authorizations can be granular, down to the field level in specific records all the way up to 10 different parameters that ... LotusScript is similar to, and may even be considered a specialized implementation of, Visual Basic, but with the addition of ...
This field specializes in the treatment of immune-mediated skin diseases such as lupus, bullous pemphigoid, pemphigus vulgaris ... visual and also data communication, but typically photos of dermatologic conditions) usually made by non-dermatologists for ... A dermatolopathologist is a pathologist or dermatologist who specializes in the pathology of the skin.[19] This field is shared ... Or they might elect to complete a post-residency fellowship.[24] This field encompasses the complex diseases of the neonates, ...
Cleanup tagged articles with a reason field from November 2013. *Wikipedia pages needing cleanup from November 2013 ... Visual disturbances. *Increased hepatic enzymes without associated clinical sequelae.. Contraindications[edit]. Avoid use in:[ ...
"Field Museum Traveling Exhibitions".. *^ a b c d e f g Nitecki, M (1980). "Field Museum of Natural History". ASC Newsletter. 8 ... Chicago: Field Museum.. *^ Metzler, S (2007). Theatres of Nature Dioramas at the Field Museum. Chicago: Field Museum of Natural ... Sue at the Field Museum. Field Museum of Natural History.. *^ "Sue at The Field Museum: The Largest, Most Complete, Best ... Field, S. (1943). Address of Mr. Stanley Field, president of the Museum. Chicago: Field Museum Press. pp. 3-5.. ...
Two of the field's major international research journals are based in Bergen: Nordic Journal for Music Therapy[80] and Voices: ... Multi-modal stimulation (MMS) includes the applications of auditory, tactile, vestibular, and visual stimulation that helps aid ... It has become well known in the music therapy field that music can be an effective tool in the treatment of grief and ... The purpose of this work is to discuss the need for additional research in the field of controlled psychiatric music therapy.[ ...
Visual field testing is an important diagnostic consideration in the evaluation of patients with many different types of ... Interpreting Visual Fields * 1. Interpreting Visual Fields Andrew White BMedSc(Hons), MBBS, PhD, FRANZCO Glaucoma consultant, ... 2. Visual Field Testing Confrontation Bjerrum Goldman Humphrey Visual Field Standard white on white SITA (Swedish Interactive ... Not every visual field defect is glaucoma! • Structural change often proceeds functional change • Progression on visual fields ...
... field.png Your Central Visual Field ((This comic contains numerous visual elements arranged around a central point, and are ... denoting where these elements would appear in someones field of vision given proper setup. For this description, elements will ... Image URL (for hotlinking/embedding): https://imgs.xkcd.com/comics/visual_ ...
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 ...
"Melbourne Rapid Fields - Visual Field Suite (MRF)" which consists of In-Clinic and Online Visual Field testing. ... "Were excited to release the Melbourne Rapid Fields - A Visual Field which allows for the user to utilize one or both products ... "Were excited to release the Melbourne Rapid Fields - A Visual Field which allows for the user to utilize one or both products ... The Online Visual Field screening allows the eyecare professional to monitor patients in the comfort of their home," says Joe ...
Central and peripheral vision is tested by using visual field tests. Changes may indicate eye diseases, such as glaucoma or ... Central and peripheral vision is tested by using visual field tests. Changes may indicate eye diseases, such as glaucoma or ...
Visual field test Humphrey visual field analyser Biased Competition Theory Divided visual field paradigm Receptive field ... 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 ... Missing or empty ,title= (help) MedlinePlus Encyclopedia: Visual Field Patient Plus Quadrantanopsia - Visual Fields Teaching ...
Receptive field size was calculated from 4 × 8° light bars. Bars were swept across the visual field at eight locations along ... We have now applied quantitative methods to characterize visual receptive fields in mouse primary visual cortex V1 by making ... of different orientations across the visual field. Figure 8 A show the radius of the receptive field (half-width at half- ... Highly Selective Receptive Fields in Mouse Visual Cortex Message Subject (Your Name) has forwarded a page to you from Journal ...
"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 Humphrey Field Analyzer, Octopus Perimeter, Optopol PTS perimeter, Oculus ... A visual field test is an eye examination that can detect dysfunction in central and peripheral vision which may be caused by ...
1 visual field impairment has rarely been noted. One reported case of unilateral visual field constriction was ascribed to an ... Visual evoked responses were normal to both pattern reversal and flash stimuli. Visual symptoms and fields remained stable ... Goldmann visual fields 37 months after start of vigabatrin treatment (case 1, top), 28 months after start of vigabatrin ... Visual fields were concentrically constricted in both eyes (fig 1 (bottom)), but funduscopy and fluorescein angiography gave ...
Visual field testing helps your doctor to determine where your side vision begins and ends. ... A visual field test is often given as part of an eye exam. ... What Is a Visual Field Test?. The visual field is the entire ... visual field exam only tests the outside of the visual field and is not as accurate as some of the other visual field tests. ... A visual field test is often given as part of an eye exam. Visual field testing helps your doctor to determine where your side ...
However, two months after surgery, she developed an inferotemporal visual field defect. Moreover, seven months after surgery, ... To report a patient who experienced visual field loss progression after vitrectomy for an idiopathic stage II macular hole. ,i, ... the patient noticed an enlargement of the temporal blind area: a nearly complete temporal defect was confirmed on visual field ... this report raises the possibility that visual field defects following macular hole surgery may be progressive. ...
The visual field technique used in this study is the standard method for quantification of visual field sensitivity. It is ... It has been shown that patients with good visual acuity (e.g., 20/20) but poor visual fields have diminished quality of life (2 ... Visual Fields Refine Understanding of Diabetic Retinopathy Progression Message Subject (Your Name) has forwarded a page to you ... Visual field sensitivity is the ability to detect a dim white spot presented at various locations on a white background and has ...
All forms of glaucoma has potentially progressing optic neuropathy that is associated with visual field loss as damage ... progresses and in which IOP is the key modifiable factor [1] Visual field... ... Visual field defects reflect visual pathway abnormalities and should correlate with the anatomic arrangement of neurons in that ... Hart WM, Becker B. The onset and evolution of glaucomatous visual field defects. Ophthalmology. 1982;89:268-79.CrossRefGoogle ...
... nearby neurons have receptive fields at nearby locations in the image. Mammalian species generally have multiple visual field ... Much of the visual cortex is organized into visual field maps: ... Much of the visual cortex is organized into visual field maps: ... while the angular representations within a cluster alternate in visual field sign. Visual field maps have been linked to ... Visual field maps in human cortex Neuron. 2007 Oct 25;56(2):366-83. doi: 10.1016/j.neuron.2007.10.012. ...
Visual Field Assessment. Full (normal) visual fields by kinetic assessment were defined as visual field results with isopters ... In full visual fields using Octopus perimetry, we found that the area of visual field obtained with the 5°/sec speed did not ... Visual field results in both groups were assessed for presence or absence of visual field defects and for the former, were ... Patients with visual field loss referred for assessment of visual field regardless of their ocular diagnosis were recruited. Of ...
Optic Nerve Optic Disc Visual Field Defect Ocular Hypertension Lamina Cribrosa These keywords were added by machine and not by ... Spaeth G.L. (1983) Regression of Optic Nerve and Visual Field Defects in Glaucoma. In: Krieglstein G.K., Leydhecker W. (eds) ... the natural history of cup progression and some specific disc-field correlations. Trans Pa Acad Ophthalmol Otolaryngo 178:255- ...
Why do you think there were so many landing fields? What factors do you think would have determined how many stops the pilot ... 1. Count how many landing fields there were between Great Falls, Montana and Fairbanks, Alaska. ...
A Humphrey Field Analyzer 10-2 test was clustered using total deviation values from 858 VFs. We stratified 68 test points into ... The aim was to establish and evaluate a new clustering method for visual field (VF) test points to predict future VF in ... Furthermore, peripheral (or full field) visual field with HFA 30-2 or 24-2 test results could not be collected in the study. ... Ogino, K. et al. Concentric division of 10 degrees visual field tests in retinitis pigmentosa. Jpn. J. Ophthalmol. 57, 268-274 ...
Visual fields. Comparison of the functional horizontal and vertical visual fields shows that the field demarcations in both ... Maximum dynamic visual field of four shark species. (A) The maximum horizontal visual fields when the eyes are in the fully ... Visual fields - physiological. The horizontal and vertical visual fields were determined for a minimum of six individuals of ... for precision as the limit of the visual field was approached. The limit of the visual field was defined as the last angle to ...
Article Wireless retina implant with large visual field Thomas Velten, Thorsten Knoll, Frank Stracke, Ronan Le Harzic, Yves ... "Wireless retina implant with large visual field" Current Directions in Biomedical Engineering, vol. 5, no. 1, 2019, pp. 53-56. ... Wireless retina implant with large visual field. De Gruyter , Published online: September 18, 2019 ... Wireless retina implant with large visual field. Current Directions in Biomedical Engineering, Vol. 5 (Issue 1), pp. 53-56. ...
... usually visual acuity visual field changes visual field defects visual field examination visual field loss visual loss visual ... fields.html?id=L3VsAAAAMAAJ&utm_source=gb-gplus-shareThe visual fields. ... The Visual Fields: A Textbook and Atlas of Clinical ..., Volume 299; Volume 1976. David O. Harrington. Snippet view - 1976. ... The visual fields: a textbook and atlas of clinical perimetry. David O. Harrington. Snippet view - 1971. ...
4B) represents the lower visual field (dorsal retina) and more medial parts of the LGN represent the upper visual field ( ... In mammals smooth retinotopic maps of the visual field are formed along the visual processing pathway whereby the left visual ... The ipsilateral visual field map V1/V2d is surrounded by regular V1, which is only representing the contralateral visual field ... Visual Field Maps in LGN.. Analysis of the retinotopic maps in the LGN was performed for each visual hemifield separately ( ...
Visualizing Visual Adaptation, Dynamic Visual Tests to Identify and Quantify Visual Damage and Repair Following Demyelination ... visual fields include Vision Training Methods for Sports Concussion Mitigation and Management, The Split Brain, Cranial ... Techniques for Investigating the Anatomy of the Ant Visual System, Finding Your Blind Spot and Perceptual Filling-in, Eye ... Measuring Connectivity in the Primary Visual Pathway in Human Albinism Using Diffusion Tensor Imaging and Tractography, ...
Removal of afferent input to the somatosensory, auditory, motor or visual cortex results in a marked change of cortical ... Changes in sensory activity can, over a period of months, alter receptive field size and … ... Receptive field dynamics in adult primary visual cortex Nature. 1992 Mar 12;356(6365):150-2. doi: 10.1038/356150a0. ... Here we remove visual input by focal binocular retinal lesions and record from the same cortical sites before and within ...
Pituitary adenoma with bitemporal visual field loss. OCT demonstrates nasal and temporal thinning of the retinal nerve fiber ... Pituitary adenoma with bitemporal visual field loss. OCT demonstrates nasal and temporal thinning of the retinal nerve fiber ...
The Killing fields of Ivory. THE KILLING FIELDS OF VORY memuco.net Two legal sales of ivory stockpiles have failed to stem the ...
Technical how-tos for Oracles Development Tools including Oracle Visual Builder Cloud Service, Oracle Developer Cloud Service ... Visual Builder. Automating Data Load into Visual Builder Business Objects. Visual Builder is often used to create apps that let ... Visual Builder. Managing Business Objects Lifecycle with Visual Builder Studio. With Visual Builder Studio the lifecycle of the ... This is a quick blog to show two techniques for adding calculated fields to an Oracle Visual Builder application. ...
Concept: Visual Field. The visual field can be loosely defined as "everything a person sees." The visual field includes ... In terms of the visual arts, the visual field is a starting point for understanding visual awareness and can become directly ... of a figure within the visual field, and motion can indicate change of size or the growth of a figure within the visual field. ... In the case of examining a painting, the visual field includes not only the painting but also the area around the painting and ...
Predictability of visual field defects in patients exposed to GABAergic agents, vigabatrin or tiagabine. Neurology1999;52(Suppl ... It was, therefore, somewhat alarming when Beran et al3 reported that they had detected visual field defects similar to those ... Nousiainen et al,4 who had earlier demonstrated a high frequency of visual field defects in vigabatrin monotherapy patients, ... Baulac M, Nordmann JP, Lanoé Y. Severe visual-field constriction and side-effects of GABA-mimetic antiepileptic agents. Lancet ...
... in the left visual field, represented by right FEF) and distractors during visual search. Large shaded circles represent ... Cooperation and competition among frontal eye field neurons during visual target selection.. Cohen JY1, Crowder EA, Heitz RP, ... Cooperation and competition among frontal eye field neurons during visual target selection ... Cooperation and competition among frontal eye field neurons during visual target selection ...
  • Glaucoma causes peripheral field defects. (wikipedia.org)
  • Macular degeneration and other diseases affecting the macula cause central field defects. (wikipedia.org)
  • The main classification of visual field defects is into Lesions to the eye's retina (heteronymous field defects in Glaucoma and AMD) Lesions of the optic nerve (heteronymous field defects) Lesions in the chiasm (e.g. (wikipedia.org)
  • Field defects are seen mainly in primary open angle glaucoma. (wikipedia.org)
  • Following are the common glaucomatous field defects: Generalized depression: Generalized depression is seen in early stages of glaucoma and many other conditions. (wikipedia.org)
  • 3 By January 1997 nine cases of visual field defects had been reported to the Committee on Safety of Medicines (Medicines Control Agency, adverse drug reactions online information tracking service), including our three cases. (bmj.com)
  • Although the beneficial results of successfully treated macular holes are unquestionable, this report raises the possibility that visual field defects following macular hole surgery may be progressive. (hindawi.com)
  • Visual field defects after pars plana vitrectomy for a full thickness, idiopathic macular hole were first documented in 1995 by Melberg and Thomas [ 1 ]. (hindawi.com)
  • All forms of glaucoma has potentially progressing optic neuropathy that is associated with visual field loss as damage progresses and in which IOP is the key modifiable factor [1] Visual field defects reflect visual pathway abnormalities and should correlate with the anatomic arrangement of neurons in that pathway [2]. (springer.com)
  • Hart WM, Becker B. The onset and evolution of glaucomatous visual field defects. (springer.com)
  • 1 Initial reports that vigabatrin use was associated with irreversible visual field defects evoked scepticism. (bmj.com)
  • 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. (bmj.com)
  • 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. (bmj.com)
  • It does not appear that such visual defects are produced by the majority of antiepileptic drugs in mainstream use-most comparative studies have compared patients taking vigabatrin with those taking carbamazepine, sodium valproate or phenytoin. (bmj.com)
  • It was, therefore, somewhat alarming when Beran et al 3 reported that they had detected visual field defects similar to those associated with vigabatrin in 6 of 12 patients exposed to tiagabine. (bmj.com)
  • Nousiainen et al , 4 who had earlier demonstrated a high frequency of visual field defects in vigabatrin monotherapy patients, failed to find any such defects in 15 patients treated with tiagabine monotherapy. (bmj.com)
  • By contrast, 53% of the vigabatrin treated patients had field defects and all had abnormal ERG results. (bmj.com)
  • The book begins with a short history of the field of perimetry and goes on to present basic clinical aspects of examination and diagnosis of visual field defects in the optic nerve, optic disc, chorioretina, optic chiasm, optic tract, lateral geniculate field bodies, and the calcarine complex. (oup.com)
  • Additional aspects of visual field examination are explored including those of monocular, binocular, and junctional field defects, congruity vs. incongruity, macular sparing vs. macular splitting, density, wedge-shaped homonymous field loss, and monocular temporal crescent. (oup.com)
  • Are there effective treatments for people who have visual field defects after stroke? (cochrane.org)
  • These problems with seeing are called visual field defects. (cochrane.org)
  • Visual field defects can make it difficult for people to function normally - especially moving about freely, avoiding obstacles, reading, driving, and taking part in rehabilitation for other stroke-related problems. (cochrane.org)
  • We wanted to see whether treatments for visual field defects could improve stroke survivors' abilities in activities of daily living (our primary outcome of interest), or other (secondary) outcomes. (cochrane.org)
  • We included 20 studies (involving 547 stroke participants) that investigated the effect of treatments for visual field defects. (cochrane.org)
  • The quality of the evidence was low to very low, and in general was insufficient to reach conclusions about the effects of interventions for people with visual field defects. (cochrane.org)
  • Visual field defects are estimated to affect 20% to 57% of people who have had a stroke. (cochrane.org)
  • Visual field defects can affect functional ability in activities of daily living (commonly affecting mobility, reading and driving), quality of life, ability to participate in rehabilitation, and depression and anxiety following stroke. (cochrane.org)
  • To determine the effects of interventions for people with visual field defects after stroke. (cochrane.org)
  • Inter-Eye Association of Visual Field Defects in Glaucoma and Its Clinical Utility. (harvard.edu)
  • No method of grading visual field (VF) defects has been widely accepted throughout the glaucoma community. (omicsonline.org)
  • The SCHEIE (Systematic Classification of Humphrey visual fields-Easy Interpretation and Evaluation) grading system for glaucomatous visual fields was created to convey qualitative and quantitative information regarding visual field defects in an objective, reproducible, and easily applicable manner for research purposes. (omicsonline.org)
  • The quantitative component incorporates the Humphrey visual field index (VFI), location of visual defects for superior and inferior hemifields, and blind spot involvement. (omicsonline.org)
  • The SCHEIE grading system is a reproducible tool that combines qualitative and quantitative measurements to grade glaucomatous visual field defects. (omicsonline.org)
  • The system aims to standardize clinical staging and to make specific visual field defects more easily identifiable. (omicsonline.org)
  • Functionally, glaucoma patients exhibit several characteristic patterns of visual field defects. (omicsonline.org)
  • Specifically, the risk of visual field defects (loss of part of the usual field of vision) was looked at with respect to driving , since the ability to drive may be one of the main motivations for undergoing surgery. (epilepsy.com)
  • Of 366 people, 276 had visual field tests before and after surgery to assess visual field defects and if they interfered with driving ability (driving-relevant defects). (epilepsy.com)
  • The surgical procedures had different risks of causing general visual field defects. (epilepsy.com)
  • The selective surgery (approach below temporal lobe) had the lowest risk for visual field defects that could affect driving. (epilepsy.com)
  • Since the ability to drive is an important aspect of most of our lives, it is important to consider the risks for visual field defects from different surgical approaches. (epilepsy.com)
  • If there is a choice of surgical approach for temporal lobe epilepsy, this study suggests that a below-temporal-lobe approach selective surgery has the lowest risk of visual field defects in general and for those that may affect driving. (epilepsy.com)
  • Results of a randomized study show both superior and inferior visual field defects impair drivers' performance on the computerized Hazard Perception Test. (ophthalmologytimes.com)
  • In the two other test situations, novel software was used to simulate superior or inferior visual field defects that were linked to the user's real-time gaze. (ophthalmologytimes.com)
  • Statistical analysis showed the effect of both visual field defects was statistically significant and also showed the impact of the superior visual field defect was significantly greater than the effect of the inferior visual field defect. (ophthalmologytimes.com)
  • The lack of good scientific evidence in this area was particularly surprising considering that driver's license eligibility requirements in the United Kingdom include some complicated criteria relating to locations of visual field defects. (ophthalmologytimes.com)
  • Homonymous visual field defects (HVFDs) are a common consequence of posterior brain injury. (rug.nl)
  • This area is not usually affected by visual field defects, and thus continues to analyse visual stimuli. (medindia.net)
  • Are visual field defects present in glaucoma? (healthtap.com)
  • By definition, glaucoma is a group of diseases which causes characteristic optic nerve damage with corresponding visual field defects . (healthtap.com)
  • There are many conditions that cause visual field defects . (healthtap.com)
  • Bilateral visual field error are defects in the visual field of both eyes. (rightdiagnosis.com)
  • However beginning field defects in computerized perimetry (MD 17dB global Moorfields classification was normal, while RB and FSM were negative in 49 of these eyes. (arvojournals.org)
  • Although computerized static perimetry allows for reliable visual field technique with high sensitivity especially for beginning glaucomatous visual field defects, Goldmann perimetry performed by an experienced operator also gives valuable results and the number of fields with glaucoma stage 0 and 1 is only 15% higher in static perimetry. (arvojournals.org)
  • Field defects caused by complete nerve fiber bundle defects will be delineated with both techniques, while kinetic perimetry often gives better delineation of the arcuate border. (arvojournals.org)
  • In general, the main arterial branch occlusion revealed congruous visual field defects with steep margins, whereas cerebral bleeding showed various types of field defects. (springer.com)
  • Middle cerebral artery occlusion showed quadrantanopia of various degrees and thalamic hemorrhage showed small homonymous field defects within one quadrant. (springer.com)
  • Haerer, A. F. Visual field defects and the prognosis of stroke patients. (springer.com)
  • Visual field defects after missile injuries to the geniculo-striate pathway in man. (springer.com)
  • We tested, whether such confounds are also evident in the normal cortical projection zone of the fovea for simulated peripheral visual field defects. (rug.nl)
  • Are visual field defects always justification for bleph? (healthtap.com)
  • You have defects in the central visual portion of your field of view - an area poorly outlined by most field testing devices. (healthtap.com)
  • Field tests will define major defects which largely will register from the peripheral areas tested. (healthtap.com)
  • Knowledge about the effects of ageing on visual field defects is very sparse. (pubmedcentralcanada.ca)
  • Long‐term follow‐up records were examined from 28 patients with light‐to‐moderate visual field defects remaining after surgery for pituitary tumours. (pubmedcentralcanada.ca)
  • 1 , 2 , 3 , 4 However, there is very little information available on the effect of ageing on visual field defects. (pubmedcentralcanada.ca)
  • A unique opportunity to evaluate the effect of ageing on non‐progressive visual field defects is provided by patients who have been operated on for pituitary tumours and can be proven free from recurrence by neuro‐imaging. (pubmedcentralcanada.ca)
  • These patients typically have bitemporal visual field defects of varying severity, with more or less normal nasal hemifields. (pubmedcentralcanada.ca)
  • Further, visual field thresholds had to be measurable in all test locations, meaning that all subjects with absolute field defects, for example temporal anopia, were excluded. (pubmedcentralcanada.ca)
  • Your responses help determine if you have a defect in your visual field. (medlineplus.gov)
  • However, two months after surgery, she developed an inferotemporal visual field defect. (hindawi.com)
  • Moreover, seven months after surgery, the patient noticed an enlargement of the temporal blind area: a nearly complete temporal defect was confirmed on visual field testing. (hindawi.com)
  • We describe a woman who, two months after surgery, developed an inferotemporal visual field defect following pars plana vitrectomy for an idiopathic macular hole. (hindawi.com)
  • Seven months after surgery, she presented an enlargement of the temporal blind area: a nearly complete temporal defect was documented on visual field testing. (hindawi.com)
  • Results were independently graded for presence/absence of field defect and for type and location of defect. (hindawi.com)
  • Octopus perimetry was reproducible for presence/absence of visual field defect. (hindawi.com)
  • Our screening protocol when using Octopus perimetry is 5°/sec for determining boundaries of peripheral isopters and 3°/sec for blind spot mapping with further evaluation of area of field loss for defect depth and size. (hindawi.com)
  • Secondary outcomes that we were interested in included the size of the visual field defect, independence (in functional abilities), quality of life, ability to scan/search for objects, reading ability, balance and falls, depression and anxiety, and adverse events. (cochrane.org)
  • Reversible Visual Field Defect After Isolated Intraventricul. (lww.com)
  • Subtypes include altitudinal hemianopsia, characterized by a visual defect above or below the horizontal meridian of the visual field. (bioportfolio.com)
  • 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. (bioportfolio.com)
  • London - Visual field loss can affect driving performance, but the extent of impairment varies depending on the location of the defect, according to the results of a study reported by Fiona C. Glen, PhD and colleagues. (ophthalmologytimes.com)
  • To test their hypothesis, that the impact of a visual field defect on driving performance depends on its location, the investigators conducted a trial in which 30 participants with healthy vision completed the driving Hazard Perception Test (HPT). (ophthalmologytimes.com)
  • The results showed that the participants' mean HPT score exceeded the passing mark in the baseline-testing situation, but not when the testing was performed with either simulated visual field defect. (ophthalmologytimes.com)
  • Compared to the baseline testing without visual field modification, HPT test scores fell 18% when the driving exam was done with the simulated superior defect and by 12% with the simulated inferior defect. (ophthalmologytimes.com)
  • She explained that interest in undertaking this study was motivated by the relative paucity of data on how different types and locations of visual field defect impact driving performance. (ophthalmologytimes.com)
  • Dr. Glen noted that the study's finding of significantly worse performance on the HPT when testing was done with the simulated superior visual field defect compared to the inferior visual field defect is not surprising considering that the superior field of view is more relevant to the driving scene. (ophthalmologytimes.com)
  • Our research is a first step toward understanding which visual field defect locations are most important for driving and in turn devising better tests for assessing fitness to drive in the future," Dr. Glen concluded. (ophthalmologytimes.com)
  • If strokes or injuries cause damage to the area of the brain that processes the information of the visual sense, this results in a visual field defect. (medindia.net)
  • What nonprocessive conditions lead to a visual field defect? (healthtap.com)
  • right homonymous field defect in 12 and left one in 25 subjects. (springer.com)
  • Relationship between visual field defect and arterial occlusion in the posterior cerebral circulation. (springer.com)
  • We applied fMRI-based visual field mapping of the central visual field at 3 T in eight controls to compare the pRF properties of the central visual field of a reference condition (stimulus radius: 14°) and two conditions with simulated peripheral visual field defect, i.e., with a peripheral gray mask, stimulating only the central 7° or 4° radius. (rug.nl)
  • as many as 25-50 percent of the photoreceptor cells may be lost before changes in visual field acuity are detected. (wikipedia.org)
  • Tests include: Full field 30-2, Full grid 24-2, Macular 10-2, Screening as well as Visual Acuity assessment. (prweb.com)
  • M&S specializes in visual acuity testing systems. (prweb.com)
  • However, the visual cortex, in which sensory coding has been most thoroughly studied in other species, has essentially been neglected in mice perhaps because of their poor spatial acuity and the lack of columnar organization such as orientation maps. (jneurosci.org)
  • Understanding visual processing in such a simple system as the mouse cortex, which lacks both fine-scale spatial acuity and maps such as orientation columns, should provide insight into the minimal mechanisms necessary for receptive field development and function. (jneurosci.org)
  • The patient showed macular hole closure and a resulting central visual acuity of 20/20. (hindawi.com)
  • Visual acuity was 20/20 in her right eye (RE) and 20/200 in her LE. (hindawi.com)
  • Follow-up examinations at seven days, 15 days, and 30 days after surgery showed a gradual improvement of visual acuity from hand motions to 20/30, an IOP within normal range under topical aqueous suppressants and normal fundus appearance together with a closed macular hole (30 days after surgery), confirmed by OCT. (hindawi.com)
  • Diabetes and diabetic retinopathy have been shown to negatively impact almost every aspect of visual function from letter acuity to night vision. (diabetesjournals.org)
  • It has been shown that patients with good visual acuity (e.g., 20/20) but poor visual fields have diminished quality of life ( 2 ). (diabetesjournals.org)
  • 1 ) show that diabetic retinopathy progresses slowly and insidiously early in its evolution, during a period when visual acuity is still intact and patients are free of symptoms ( Fig. 1 ). (diabetesjournals.org)
  • 60 patients with binocular paracentral scotomata but normal visual acuity (VA) were recruited prospectively. (nih.gov)
  • How is visual acuity preserved in bitemporal hemianopia? (healthtap.com)
  • What is combined visual acuity (combined vision)? (healthtap.com)
  • Combined visual acuity is the best that you can see with both eyes open. (healthtap.com)
  • Though one would think that it can only be as good as the better seeing eye , often combined visual acuity is better than that. (healthtap.com)
  • The preoperative and postoperative visual acuity was compared. (thefreelibrary.com)
  • We did phacoemulsification or ECCE with IOL implantation in most of our cases and aim of the study was to see if we could achieve postoperative visual acuity as good as achieved in the industrialized countries. (thefreelibrary.com)
  • A detailed ophthalmic examination (including visual acuity, pupillary examination, slit lamp biomicroscopy, and applanation tonometery) was carried out. (thefreelibrary.com)
  • Is it possible to get accurate visual field test with macular pucker decline in visual acuity, lights less bright & white computer screen looking gray? (healthtap.com)
  • We have now applied quantitative methods to characterize visual receptive fields in mouse primary visual cortex V1 by making extracellular recordings with silicon electrode arrays in anesthetized mice. (jneurosci.org)
  • iii ) In primary visual cortex V1, the contralateral visual hemifield is represented in a smooth, topographically organized map which, in primates, is subdivided into columnar systems representing the 2 eyes and various feature domains such as orientation, spatial frequency, and color. (pnas.org)
  • Through massively parallel computational simulations, we studied how a large network of simple neural elements (the RF-LISSOM model) could develop a functional organization similar to that of the primary visual cortex. (utexas.edu)
  • The area most commonly affected is the primary visual cortex, the first processing point for visual input to the cerebral cortex. (medindia.net)
  • 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. (frontiersin.org)
  • but it's also helpful for retinal conditions and instances when visual field function needs to be measured. (slideshare.net)
  • Visual fields in retinal disease. (medlineplus.gov)
  • The investigators measured the visual field sensitivity of patients with diabetes both with and without mild to moderate diabetic retinopathy, as defined by retinal vascular lesions. (diabetesjournals.org)
  • Because the early visual field deficits in the current study were not correlated with typical risk factors such as blood glucose control or retinal appearance, the clinical assessment of vision beyond the standard letter chart should be investigated for detection of patients at risk for diabetic retinopathy. (diabetesjournals.org)
  • Here we remove visual input by focal binocular retinal lesions and record from the same cortical sites before and within minutes after making the lesion and find immediate striking increases in receptive field size for cortical cells with receptive fields near the edge of the retinal scotoma. (nih.gov)
  • Retinal dystrophies such as retinitis pigmentosa, degenerative conditions such as advanced stage glaucoma , vascular conditions such as occipital stroke , and post traumatic conditions such as traumatic optic neuropathy all can constrict visual fields. (healthtap.com)
  • Previous studies demonstrated that alterations in functional MRI derived receptive field (pRF) properties in cortical projection zones of retinal lesions can erroneously be mistaken for cortical large-scale reorganization in response to visual system pathologies. (rug.nl)
  • 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. (frontiersin.org)
  • To discuss the case of a patient with severely reduced visual fields arising from terminal glaucomatous retinal damage and the treatment of this condition by spinal manipulation. (chiro.org)
  • Commonly used perimeters are the automated Humphrey Field Analyzer, Optopol Perimeters, Octopus, the Heidelberg Edge Perimeter, or the Oculus. (wikipedia.org)
  • Heijl A, Patella VM, Bengtsson B. The field analyzer primer: effective perimetry. (springer.com)
  • A Humphrey Field Analyzer 10-2 test was clustered using total deviation values from 858 VFs. (nature.com)
  • Twenty-one subjects were examined using the Humphrey Field Analyzer, using SITA programs, and 40 with high-pass resolution perimetry (HRP). (biomedsearch.com)
  • This Humphrey Field Analyzer Model 750 comes with wheelchair accessible table and printer. (optiboard.com)
  • The Humphrey Field Analyzer is the most widely accepted machine used to quantify visual field loss in clinical practice and research studies, with Standard Automated Perimetry (SAP) serving as the standard for assessing visual field damage [ 5 ]. (omicsonline.org)
  • This quantitative description of receptive field properties should facilitate the use of mouse visual cortex as a system to address longstanding questions of visual neuroscience and cortical processing. (jneurosci.org)
  • Over the past nearly half century since visual responses were first described in the mammalian visual cortex ( Hubel and Wiesel, 1962 ), there has been intensive research into the neural circuit and developmental mechanisms that give rise to selective receptive field (RF) properties. (jneurosci.org)
  • Much of the visual cortex is organized into visual field maps: nearby neurons have receptive fields at nearby locations in the image. (nih.gov)
  • In the visual cortex, islands of ipsilateral visual field representations were located along the representations of the vertical meridian. (pnas.org)
  • The human cerebral cortex contains continuous topographic maps for auditory, visual, and somatosensory inputs and motor cortex outputs ( 1 - 4 ). (pnas.org)
  • Removal of afferent input to the somatosensory, auditory, motor or visual cortex results in a marked change of cortical topography. (nih.gov)
  • At the level of the lateral geniculate nucleus, which provides the visual input to the striate cortex, a large silent region remains. (nih.gov)
  • Activations in visual cortex for irrelevant peripheral stimulation decreased with increasing attentional load at fixation. (psu.edu)
  • We report quantitative estimates of pRF size in medial, lateral and ventral occipital regions of human visual cortex. (psu.edu)
  • The conclusion is that the lateral connections in the cortex could act as as a negative filter that allows the cortex to efficiently process the massive amounts of visual information presented by the environment. (utexas.edu)
  • Consequently, our results imply that, previously reported similar findings in patients with actual peripheral scotomas need to be interpreted with caution and indicate the need for adequate control conditions in investigations of visual cortex reorganization. (rug.nl)
  • The resulting sympathetic irritation is presumed to lead to vasoconstriction of the vertebral-basilar arterial system, producing an ischemic condition of the brainstem and occipital lobe (ie, including the visual cortex). (chiro.org)
  • Tangent screen or Goldmann field exam. (medlineplus.gov)
  • The tangent screen exam (Goldmann field exam) can be conducted in your eye doctor's office. (healthline.com)
  • To determine diagnostic accuracy of kinetic visual field assessment by Octopus 900 perimetry compared with Goldmann perimetry. (hindawi.com)
  • Comparison of test duration and type of visual field classification for Octopus versus Goldmann perimetry. (hindawi.com)
  • Goldmann kinetic perimetry has been an essential perimetry assessment in many areas of ophthalmology practice including the assessment of young children, patients with poor vision or severely restricted visual fields, and patients with brain injury involving the posterior hemispheres of the brain [ 1 - 5 ]. (hindawi.com)
  • The Goldmann perimeter is primarily a kinetic perimetry and uses a mobile target of fixed luminosity with which positions of equal sensitivity are plotted perpendicularly to the limits of the expected visual fields or isopters through the free movement of the target in all directions [ 6 ]. (hindawi.com)
  • Goldmann perimetry is a three variable visual field examination with consideration of background illumination, stimulus luminosity, and stimulus size. (hindawi.com)
  • Although the Octopus 900 perimeter provides age/matched comparisons from its data bank from which comparisons can be made of new visual field results, there is little data available in the literature on the comparison of kinetic visual field results obtained by Goldmann versus Octopus 900 perimetry. (hindawi.com)
  • Goldmann perimetry offers the option to more clearly delineate the remaining visual field in advanced deterioration. (arvojournals.org)
  • One hundred and thirty patients of cerebrovascular accidents were subjected to a visual field examination using a Static Campimeter and a Goldmann perimeter. (springer.com)
  • In optometry, ophthalmology, and neurology, a visual field test is used to determine whether the visual field is affected by diseases that cause local scotoma or a more extensive loss of vision or a reduction in sensitivity (increase in threshold). (wikipedia.org)
  • Investigative Ophthalmology & Visual Science July 2018, Vol.59, 5107. (arvojournals.org)
  • Investigative Ophthalmology & Visual Science April 2010, Vol.51, 5495. (arvojournals.org)
  • Professor of Ophthalmology at Harvard Medical School and the Moakley Scholar in Aging Eye Research at the Schepens Eye Research Institute of Mass. Eye and Ear, has been developing prism devices to expand the visual field for these patients for more than 15 years. (masseyeandear.org)
  • Visual evoked responses were normal to both pattern reversal and flash stimuli. (bmj.com)
  • Under natural viewing conditions, the visual field is cluttered with a multitude of salient yet irrelevant stimuli. (frontiersin.org)
  • As such, the visual system constantly performs the complex process of selecting behaviorally relevant stimuli whilst ignoring extraneous stimuli. (frontiersin.org)
  • Attentional enhancement and suppression of stimuli in the visual field does not occur invariably but is modulated by the demands of the task at hand. (frontiersin.org)
  • We varied the attentional load of a visual monitoring task performed on a rapid stream at central fixation without altering the central stimuli themselves, while measuring the impact on fMRI responses to task-irrelevant peripheral checkerboards presented either unilaterally or bilaterally. (psu.edu)
  • The new method computes a model of the population receptive field from responses to a wide range of stimuli and estimates the visual field map as well as other neuronal population properties, such as receptive field size and laterality. (psu.edu)
  • A team of researchers has found that patients who are blind in one side of their visual field were able to improve the visual detection of light stimuli in the blind half when they were passively made to hear sounds from the affected side. (medindia.net)
  • Likewise, neural firing of a neuron can strongly be influenced by stimuli outside the classical receptive field. (epfl.ch)
  • Cortical maps are arranged into clusters in which several maps have parallel eccentricity representations, while the angular representations within a cluster alternate in visual field sign. (nih.gov)
  • In V1, smooth and continuous maps from contra- and ipsilateral hemifield overlap each other, whereas in ventral V2 and V3 ipsilateral quarter field representations invaded small distinct cortical patches. (pnas.org)
  • Changes in sensory activity can, over a period of months, alter receptive field size and cortical topography. (nih.gov)
  • After a few months even the cortical areas that were initially silenced by the lesion recover visual activity, representing retinotopic loci surrounding the lesion. (nih.gov)
  • We quantified, for the cortical representation of the actually stimulated visual field, the changes in the position and size of the pRFs associated with reduced peripheral stimulation using conventional and advanced pRF modeling. (rug.nl)
  • 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. (frontiersin.org)
  • 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. (frontiersin.org)
  • These analyses revealed age-dependent cortical thinning specific to peripheral visual field representations in anterior portions of V1, but did not provide evidence for age-dependent cortical thinning in other portions of V1. (frontiersin.org)
  • A visual field test is an eye examination that can detect dysfunction in central and peripheral vision which may be caused by various medical conditions such as glaucoma, stroke, pituitary disease, brain tumours or other neurological deficits. (wikipedia.org)
  • Techniques used to perform this test include the confrontation visual field examination (Donders' test). (wikipedia.org)
  • Intraocular pressure before and after visual field examination. (biomedsearch.com)
  • PURPOSE: To evaluate the influence of visual field (VF) examinations using modern techniques with short examination times on the intraocular pressure (IOP). (biomedsearch.com)
  • 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. (oup.com)
  • In all, this volume provides a very useful overview of the techniques, both old and new, of visual field examination in a multiplicity of eye disorders and as such will be of interest to all ophthalmologists, neuro-opthalmologists, retina specialists, and optomestrist. (oup.com)
  • 8 It was recommended that at least one of these tests be performed, when available, in addition to 10-2 visual field (10-2 VF) testing, which was the standard screening test supplementing ophthalmic examination since previous guidelines of 2002. (dovepress.com)
  • To present a visual field examination method using virtual reality glasses and evaluate the reliability of the method by comparing the results with those of the Humphrey perimeter. (dovepress.com)
  • Visual field examination results using virtual reality glasses have a high correlation with the Humphrey perimeter allowing the method to be suitable for probable clinical use. (dovepress.com)
  • Before commencing chiropractic spinal manipulative therapy, an ophthalmologic examination was performed, and visual performance was monitored through a course of treatment. (chiro.org)
  • Every patient underwent a yearly neuro‐ophthalmological examination, including an automated visual field examination. (pubmedcentralcanada.ca)
  • Lehrer said 147 eyes had at least one reliable visual field at both preoperative and postoperative time points, with a mean postoperative visual field at 37.7 months. (healio.com)
  • Merging of monocular field tests (Integrated Visual Field, IVF) has been proposed as an alternative for glaucoma patients. (nih.gov)
  • Patterns of Daily Physical Activity across the Spectrum of Visual Field Damage in Glaucoma Patients. (harvard.edu)
  • An objective method for classifying and grading visual field damage in glaucoma patients is needed. (omicsonline.org)
  • Lesions of the visual pathway cause characteristic forms of visual disturbances, including homonymous hemianopsia, quadrantanopsia, and scotomata. (wikipedia.org)
  • In mammals smooth retinotopic maps of the visual field are formed along the visual processing pathway whereby the left visual field is represented in the right hemisphere and vice versa. (pnas.org)
  • Visual Fields via the Visual Pathway, Second Edition 2nd Edition by Fiona Rowe and Publisher CRC Press. (vitalsource.com)
  • The standardized visual field assessment, which measures visual function in 76 locations of the central visual area, is an important diagnostic tool in the treatment of the eye disease glaucoma. (sciweavers.org)
  • Automatic techniques to classify patients based on this assessment have had limited success, primarily due to the high variability of individual visual field measurements. (sciweavers.org)
  • At the beginning of the current COVID-19 crisis, there was significant uncertainty about the risk for COVID-19 transmission between patients when undertaking a visual field assessment at a bowl perimeter. (college-optometrists.org)
  • Hasinger, Gerhard and Fliessbach, Andreas (2016) The Spade Test - Visual Soil Assessment in the Field. (orgprints.org)
  • Within the project FertilCrop, visual soil assessment and other hands-on techniques are compared to analytical soil tests. (orgprints.org)
  • Another method is for the practitioner to hold up 1, 2 or 5 fingers in the four quadrants and center of a patient's visual field (with the other eye covered). (wikipedia.org)
  • Machine based tests aid diagnostics by allowing a detailed printout of the patient's visual field. (wikipedia.org)
  • The examiner will then move his hand out of the patient's visual field and then bring it back in. (wikipedia.org)
  • The computer then automatically maps and calculates the patient's visual field. (wikipedia.org)
  • IV) In primates visual areas V2 and V3 contain maps of quarterfield representations of upper and lower contralateral visual fields that are mirrored along the representations of the vertical and horizontal meridians between adjacent areas ( 3 , 10 , 11 ). (pnas.org)
  • Also, we quantify the amount of input from ipsi- and contralateral visual fields. (psu.edu)
  • This article describes the test that measures your visual field. (medlineplus.gov)
  • Perimetry or campimetry is one way to systematically test the visual field. (wikipedia.org)
  • failed verification] It is the systematic measurement of differential light sensitivity in the visual field by the detection of the presence of test targets on a defined background. (wikipedia.org)
  • A visual field test is used to assess a person's central and peripheral vision and detect signs of glaucoma damage to the optic nerve, eyelid conditions such as ptosis, optic nerve disease, and diseases that affect visual pathways in the brain. (medicinenet.com)
  • What Is a Visual Field Test? (healthline.com)
  • A visual field test is often given as part of an eye exam. (healthline.com)
  • The visual field can be tested in a few different ways, including the confrontational visual field exam, tangent screen test, and automated perimetry exam (described below). (healthline.com)
  • However, this test can help your doctor decide if further visual field testing is needed. (healthline.com)
  • The automated perimetry test uses a computer program to test an individual's visual field. (healthline.com)
  • The aim was to establish and evaluate a new clustering method for visual field (VF) test points to predict future VF in retinitis pigmentosa. (nature.com)
  • At the 3 study visits exposed to a training session (simulated visual field test on a computer). (clinicaltrials.gov)
  • which requires more work than just checking the private field holding the cache (and the more code I write, the more likely it is that my test will have a bug in it). (visualstudiomagazine.com)
  • The binocular Esterman visual field test (EVFT) is the current visual field test for driving in the UK. (nih.gov)
  • To examine the level of agreement between the EVFT and IVF for patients with binocular paracentral scotomata, caused by either ophthalmological or neurological conditions, and to compare outcomes with useful field of view (UFOV) performance, a test of visual attention thought to be important in driving. (nih.gov)
  • To develop and test a visual analytics tool to help clinicians identify systematic and clinically meaningful patterns in patient-generated data (PGD) while decreasing perceived information overload. (bioportfolio.com)
  • The Hodapp, Parrish, and Anderson System (HPA) system, a commonly used classification system, is based upon the overall extent of visual field depression (calculated by the mean deviation value), the number of defective points in the Humphrey Statpac-2 pattern deviation probability map of the 24-2, SITA-STANDARD test, and proximity to damage to fixation point [ 7 ]. (pubmedcentralcanada.ca)
  • Furthermore, the use of the binocular visual field test to assess fitness to drive is questionable since it was never developed for that purpose and has many specifications that are not necessarily relevant to driving," she said. (ophthalmologytimes.com)
  • However, it is an important finding because the visual field test that is used for determining driving eligibility in the United Kingdom is weighted toward the inferior visual field," she said. (ophthalmologytimes.com)
  • Virtual reality glasses, a smartphone with a 6 inch display, and software that implements a fast-threshold 3 dB step staircase algorithm for the central 24° of visual field (52 points) were used to test 20 eyes of 10 patients, who were tested in a random and consecutive order as they appeared in our glaucoma department. (dovepress.com)
  • 0.0001) was found between the virtual reality visual field test and the Humphrey perimeter visual field. (dovepress.com)
  • To investigate the effectiveness of the auditory stimulation, the research team carried out a visual test before and after the acoustic stimulation. (medindia.net)
  • Can a large eye floater affect peripheral vision in a visual field test. (healthtap.com)
  • If you need to conduct a visual field test, consider using an enclosed visual field screener rather than a bowl type, because an enclosed visual field screener is easier to disinfect. (college-optometrists.org)
  • The Humphrey visual field is a diagnostic test to measure visual fields, or perimetry. (cincinnatieye.com)
  • The Humphrey visual field test measures the entire area of peripheral vision that can be seen while the eye is focused on a central point. (cincinnatieye.com)
  • During this test, lights of varying intensities appear in different parts of the visual field while the patient's eye is focused on a certain spot. (cincinnatieye.com)
  • The Humphrey visual field test can also be used to detect conditions within the optic nerve of the eye, and certain neurological conditions as well. (cincinnatieye.com)
  • Visual field test result normal - 3/14 fixation error. (healthtap.com)
  • Normal field vision test. (healthtap.com)
  • If field is normal, that is a good sign( how did they test this or make that claim? (healthtap.com)
  • Exposure time is 165 ms. Using targets stepped by 0.1 log unit in size, the smallest discernible size is determined in 50 test locations between 6 and 28 degrees of visual field radius. (pubmedcentralcanada.ca)
  • This presentation will follow the progression of visual field loss and neurological deterioration as a result of HIV infection in a previously undiagnosed patient. (aaopt.org)
  • The aim of this Cochrane Review was to find out whether iridotomy compared to no iridotomy can slow progression of visual field loss in (1) people with primary angle-closure glaucoma, (2) people with primary angle closure, and (3) people who are suspected of having primary angle closure. (cochrane.org)
  • At the time of review , it is uncertain whether iridotomy can slow progression of visual field loss. (cochrane.org)
  • At present, we cannot draw reliable conclusions based on randomized controlled trials as to whether iridotomy slows progression of visual field loss at one year compared to no iridotomy. (cochrane.org)
  • The effectiveness of iridotomy on slowing progression of visual field loss, however, is uncertain. (cochrane.org)
  • The visual field technique used in this study is the standard method for quantification of visual field sensitivity. (diabetesjournals.org)
  • Visual field sensitivity is the ability to detect a dim white spot presented at various locations on a white background and has important functional implications: It is important for mobility, driving, and other important tasks of daily living. (diabetesjournals.org)
  • However, the magnitude of reduced visual field sensitivity was modest, ranging from -0.19 dB to -1.26 dB, a change similar to that noted by Scott et al. (diabetesjournals.org)
  • The purpose of this study was to determine the relative sensitivity and specificity of 10-2 visual fields (10-2 VFs), multifocal electroretinography (mfERG), and spectral domain optical coherence tomography (SD-OCT) in detecting hydroxychloroquine retinopathy. (dovepress.com)
  • The name comes from the method of testing the perimeter of the visual field. (wikipedia.org)
  • We find that, although the spatial scale of mouse receptive fields is up to one or two orders of magnitude larger, neurons show selectivity for stimulus parameters such as orientation and spatial frequency that is near to that found in other species. (jneurosci.org)
  • We survey recent measurements of human visual field maps, describe hypotheses about the function and relationships between maps, and consider methods to improve map measurements and characterize the response properties of neurons comprising these maps. (nih.gov)
  • Cooperation and competition among frontal eye field neurons during visual target selection. (nih.gov)
  • We simultaneously recorded activity from multiple frontal eye field neurons and asked whether they interacted to select targets from distractors during visual search. (nih.gov)
  • When both neurons in a pair selected the target and had overlapping receptive fields (RFs), they cooperated more than when one or neither neuron in the pair selected the target, measured by positive spike timing correlations using joint peristimulus time histogram analysis. (nih.gov)
  • Thus, we provide evidence for dynamic and task-dependent cooperation and competition among frontal eye field neurons during visual target selection. (nih.gov)
  • I discuss how the notion of neural fields, a phenomenological averaged description of spatially distributed populations of neurons, can be used to build models of how visual information is represented and processed in the visual areas of primates. (inria.fr)
  • The more neurons die in this brain area, the bigger the visual deficit. (medindia.net)
  • 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. (medlineplus.gov)
  • Central and peripheral vision is tested by using visual field tests. (medlineplus.gov)
  • Visual field testing helps your doctor to determine where your side vision (peripheral vision) begins and ends and how well you can see objects in your peripheral vision. (healthline.com)
  • What is the difference between visual field loss and peripheral vision loss? (healthtap.com)
  • The visual field is the entire area of vision whereas peripheral vision is a subset of the field. (healthtap.com)
  • Some peripheral vision loss not in field of vision. (healthtap.com)
  • In total, 117 eyes had both one reliable OCT and visual field at preoperative and postoperative time points. (healio.com)
  • Visual field loss may occur due to many disease or disorders of the eye, optic nerve, or brain. (wikipedia.org)
  • This eye exam will show whether you have a loss of vision anywhere in your visual field. (medlineplus.gov)
  • This type of perimetry is the most commonly used in clinical practice, and in research trials where loss of visual field must be measured. (wikipedia.org)
  • To report a patient who experienced visual field loss progression after vitrectomy for an idiopathic stage II macular hole. (hindawi.com)
  • Since then, this complication has been reported by a number of authors who have described peripheral visual field loss that occurred after disappearance of the gas bubble and remained unchanged during the follow-up period [ 1 - 7 ]. (hindawi.com)
  • but in 18 cases, the cause of visual loss was not determined. (diabetesjournals.org)
  • Kuzmiene L. (2019) Visual Field Loss in Glaucoma. (springer.com)
  • Prospective cross section evaluation of 40 control subjects with full visual fields and 50 patients with known visual field loss. (hindawi.com)
  • Despite the complete loss of her right hemisphere (di- and telencephalon) at birth, the patient's remaining hemisphere has not only developed maps of the contralateral (right) visual hemifield but, surprisingly, also maps of the ipsilateral (left) visual hemifield. (pnas.org)
  • The suitability of the UFOV for assessing crash risk in those with visual field loss is questionable. (nih.gov)
  • Specific patterns of visual field loss may also be associated with genetic variants in future genetic analysis. (omicsonline.org)
  • However, there is no universally agreed upon standard for grading the diversity of patterns of visual field loss. (omicsonline.org)
  • Partial or complete loss of vision in one half of the visual field(s) of one or both eyes. (bioportfolio.com)
  • They concluded that, "the CLS may be useful to assess the risk of future functional loss, even in situations when insufficient historical visual field information is available. (healio.com)
  • The CLS not only showed a more complete picture of IOP, but may allow us to project future functional loss even with minimal visual field history. (healio.com)
  • However, superior visual field loss is associated with significantly greater worsening than inferior visual field loss. (ophthalmologytimes.com)
  • Binocular visual field loss has been linked to subject-reported driving difficulties and risk of motor vehicle accidents," said Dr. Glen, postdoctoral research assistant, Department of Optometry and Visual Science, School of Health Sciences, City University London. (ophthalmologytimes.com)
  • Elevated IOP is associated with glaucomatous optic nerve damage and visual field loss. (cochrane.org)
  • Could laser eye surgery correct loss of visual field vision? (healthtap.com)
  • Many insurance companies are not covering for only loss of visual field . (healthtap.com)
  • Recovery of vision in this patient was an unexpected and remarkable outcome, raising the question of whether chiropractic spinal manipulative therapy may be of value in the management of glaucomatous visual field loss. (chiro.org)
  • The rate of age‐related loss of neural channels appears to be identical in normal and abnormal visual field areas in subjects with stable mid‐chiasmal lesions. (pubmedcentralcanada.ca)
  • A single case of visual field constriction associated with prolonged treatment with the GABA agonist drug progabide has been reported, 2 but this drug is not in widespread use. (bmj.com)
  • Visual field maps have been linked to functional and perceptual properties of the visual system at various spatial scales, ranging from the level of individual maps to map clusters to dorsal-ventral streams. (nih.gov)
  • 6 . A method in accordance with claim 4 , wherein the tuning includes increasing the spatial frequency of the grating until the illusion is not properly detected by the subject and then maintaining the spatial frequency at a level that is detectable by the subject, yet near the limit of the spatial resolution of the subject's central visual field. (google.com.au)
  • Contextual modulation is often seen as a limitation of the visual system, where nearby flankers impede spatial resolution and thus deteriorate performance on target elements. (epfl.ch)
  • These findings indicate the dependence of foveal pRF parameters on the spatial extent of the stimulated visual field and are likely associated with methodological biases and/or physiological mechanisms. (rug.nl)
  • There are many variants of this type of exam (e.g., wiggling fingers at visual periphery in the cardinal axes). (wikipedia.org)
  • Confrontation visual field exam. (medlineplus.gov)
  • What Happens During the Confrontational Visual Field Exam? (healthline.com)
  • The confrontational visual field exam is a basic exam performed by your eye doctor. (healthline.com)
  • The confrontational visual field exam only tests the outside of the visual field and is not as accurate as some of the other visual field tests. (healthline.com)
  • This study will look at the effects of a computer program that allows new patients to practice the visual field exam before taking the actual exam. (clinicaltrials.gov)
  • I would not however expect a large visual field abnormality from a floater and certainly l recommend an exam to rule out any problems by an eye md. (healthtap.com)
  • Visual field testing is an important diagnostic consideration in the evaluation of patients with many different types of pathologies. (slideshare.net)
  • The Online Visual Field screening allows the eyecare professional to monitor patients in the comfort of their home," says Joe Marino, President & CEO. (prweb.com)
  • The manufacturers of vigabatrin had received 28 reports of visual field abnormalities worldwide by January 1997 in an estimated 140 000 patients treated (Hoechst Marion Roussel, personal communication). (bmj.com)
  • 1 ) provide one of the first natural history descriptions of early visual function abnormalities in patients with early-stage diabetic retinopathy. (diabetesjournals.org)
  • are that the authors enrolled 81 well-characterized patients and measured visual fields over 5 years: every 6 months during the first 3 years and annually during the final 2 years. (diabetesjournals.org)
  • At study end, 22% of patients exhibited significant worsening of the visual field, defined by standard criteria from glaucoma studies. (diabetesjournals.org)
  • Interestingly, worsening of the visual field occurred in patients with and without changes in vascular lesions associated with diabetic retinopathy. (diabetesjournals.org)
  • An obvious question is whether the 20% of patients with worsening visual fields are at higher risk of progression to advanced disease. (diabetesjournals.org)
  • None of the tiagabine treated patients displayed any abnormality of visual field and their ERG results did not diverge from normal. (bmj.com)
  • Although patient numbers remain small (only 11 of the tiagabine treated patients were able to produce reliable visual fields), these results, taken with those of Nousiainen et al , 4 indicate that visual field constriction is at worst a much rarer side effect of tiagabine than vigabatrin, and at best may not occur with the drug. (bmj.com)
  • Controlled study comparing visual function in patients treated with vigabatrin and tiagabine. (bmj.com)
  • Both IOP and medication use were reduced and glaucoma did not progress in the majority of patients in a study looking at 5-year visual field and OCT outcomes after iStent implantation in a real-world clinical setting. (healio.com)
  • Assessing visual fields for driving in patients with paracentral scotomata. (nih.gov)
  • Patients who underwent at least three prior reliable visual field tests were examined. (healio.com)
  • Patients were asked to determine the position of light flashes in the healthy and in the blind field of vision. (medindia.net)
  • In other treatments, the patients undergo arduous and time-consuming visual training" explains Lewald. (medindia.net)
  • Therefore, remaining visual functions are retained in the blind half, which the patients, however, are not aware of. (medindia.net)
  • Visual field testing will occasionally pickup small areas of visual field depressions if the floater is particularly large and thick, as some patients may have. (healthtap.com)
  • Six patients (4.2%) had a poor visual outcome (best corrected vision less than 6/60). (thefreelibrary.com)
  • Mean intrasellar pressure, visual field, headache intensity and quality of life of patients with pituitary adenoma. (biomedsearch.com)
  • Boston, Mass. - Researchers from the Schepens Eye Research Institute of Massachusetts Eye and Ear and Harvard Medical School have designed three new eyeglasses using high-power prisms to optimally expand the visual fields of patients with hemianopia, a condition in which the visual fields of both eyes are cut by half. (masseyeandear.org)
  • Patients with hemianopia cannot legally drive in Massachusetts, where a visual field of 120 degrees is required. (masseyeandear.org)
  • Their most recent commercially available device introduced in 2013, the peripheral prism glasses , has been shown to expand the visual fields of patients with hemianopia by as much as 30 degrees, optically shifting objects from the blind side of the visual field to the seeing side. (masseyeandear.org)
  • The new optical devices can improve the functionality of the current prism devices used for visual field expansion and may find use in various other field expansion applications such as a mobility aid for patients with tunnel vision," Dr. Peli said. (masseyeandear.org)
  • Although numerous studies have been published, few studies have described the natural history of the visual function abnormalities associated with this disease. (diabetesjournals.org)
  • The binocular visual field is the superimposition of the two monocular fields. (wikipedia.org)
  • There are three primary measurements of the visual field: single eye (monocular), both eyes combined (cyclopean) and overlap of two monocular fields (binocular) ( Collin and Shand, 2003 ). (biologists.org)
  • The point closest to the eyes at which the monocular fields overlap is termed the binocular convergence point, and the distance from this point to the central point midline of the head is the convergence distance. (biologists.org)
  • Damage of superior or/and inferior nerve fiber bundle appears as arcuate scotoma in superior or/and inferior visual field (Fig. 16.1). (springer.com)
  • 2 A literature search found brief details of one other case of bilateral field constriction apparently induced by vigabatrin. (bmj.com)
  • See detailed information below for a list of 13 causes of Bilateral visual field error , Symptom Checker , including diseases and drug side effect causes. (rightdiagnosis.com)
  • The following medical conditions are some of the possible causes of Bilateral visual field error. (rightdiagnosis.com)
  • Listed below are some combinations of symptoms associated with Bilateral visual field error, as listed in our database. (rightdiagnosis.com)
  • Review further information on Bilateral visual field error Treatments . (rightdiagnosis.com)
  • Read more about causes and Bilateral visual field error deaths . (rightdiagnosis.com)
  • How Common are these Causes of Bilateral visual field error? (rightdiagnosis.com)
  • This information refers to the general prevalence and incidence of these diseases, not to how likely they are to be the actual cause of Bilateral visual field error. (rightdiagnosis.com)
  • The following list of conditions have ' Bilateral visual field error ' or similar listed as a symptom in our database. (rightdiagnosis.com)
  • The human pRF size estimates in V1-V3 agree well with electrophysiological receptive field measurements at a range of eccentricities in corresponding locations within monkey and human visual field maps. (psu.edu)
  • Comparison of visual fields with HRT measurements mostly demonstrated more serious morphological damage, as expected. (arvojournals.org)
  • Though visual complaints such as diplopia have occasionally been reported with vigabatrin use, 1 visual field impairment has rarely been noted. (bmj.com)
  • Wireless retina implant with large visual field" Current Directions in Biomedical Engineering , vol. 5, no. 1, 2019, pp. 53-56. (degruyter.com)
  • Microsoft announced Visual Studio 2019 v16.10 Preview 2, focusing on "developer productivity and convenience" with new features for .NET, Containers, C++, Accessibility and more. (visualstudiomagazine.com)
  • In this study we tested the 'enhanced binocular field' hypothesis (that proposes enhanced frontal binocularity) by comparison of the visual fields of three hammerhead species: the bonnethead shark, Sphyrna tiburo , the scalloped hammerhead shark, Sphyrna lewini , and the winghead shark, Eusphyra blochii , with that of two carcharhinid species: the lemon shark, Negaprion brevirostris , and the blacknose shark, Carcharhinus acronotus . (biologists.org)
  • This study illustrates the larger binocular overlap in hammerhead species relative to their carcharhinid sister taxa and is consistent with the 'enhanced binocular field' hypothesis. (biologists.org)
  • Perimetry more carefully maps and quantifies the visual field, especially at the extreme periphery of the visual field. (wikipedia.org)
  • In the case of examining a painting, the visual field includes not only the painting but also the area around the painting and any shapes that can be perceived in the periphery of vision. (nmu.edu)
  • Usually the entire half of the visual field is affected, a condition known as hemianopia. (medindia.net)
  • Impairing either the left or right halves of the visual fields in both eyes, hemianopia affects more than one million Americans and is most commonly caused by stroke, brain tumors and head trauma. (masseyeandear.org)
  • Hemianopia reduces the natural visual field of about 180 degrees to a mere 90 degrees. (masseyeandear.org)
  • One method of treatment for hemianopia is to expand the visual field with prisms mounted on or embedded in eyeglasses. (masseyeandear.org)
  • Read RM, Spaeth GL (1974) The practical clinical appraisal of the optic disc in glaucoma: the natural history of cup progression and some specific disc-field correlations. (springer.com)
  • In the mammalian visual system, map formation depends on a succession of developmental decisions. (pnas.org)
  • We are most concerned with progression in the order of 1.5-2dB per year Common RoP (0.6 dB/year) in a clinical population with glaucoma Mean RoP for normal visual decay (0.07 dB/year) Mean RoP (1.1 dB/year) in untreated glaucoma Heijl et al. (slideshare.net)
  • CDBME is as BME-BMT a forum for the exchange of knowledge in the fields of biomedical engineering, medical information technology and biotechnology/bioengineering for medicine and addresses engineers, natural scientists, and clinicians working in research, industry, or clinical practice. (degruyter.com)
  • Make the best use of Scientific Research and information from our 700+ peer reviewed, Open Access Journals that operates with the help of 50,000+ Editorial Board Members and esteemed reviewers and 1000+ Scientific associations in Medical, Clinical, Pharmaceutical, Engineering, Technology and Management Fields. (omicsonline.org)
  • Alesi Surgical received FDA approval for the Ultravision™ Visual Field Clearing System on 4 May 2020. (sages.org)
  • Semiautomated kinetic perimetry produced similar results for detection and localisation of area of visual field deficit and was deemed reliable and reproducible [ 7 , 8 ]. (hindawi.com)
  • We introduce functional MRI methods for estimating the neuronal population receptive field (pRF). (psu.edu)
  • Assessing Functional Disability in Glaucoma: The Relative Importance of Central Versus Far Peripheral Visual Fields. (harvard.edu)
  • Light spot patterns testing the central 24 degrees or 30 degrees of the visual field, are most commonly used. (wikipedia.org)
  • Visual fIeld good,nerve damage 30-45%.Would vitrectomy cause glaucoma to progress? (healthtap.com)
  • Most of the early glaucomatous changes are seen within the central visual field, mainly in Bjerrum's area, 10°-20° from fixation. (wikipedia.org)
  • Alteration of a fixation or peripheral stimulus displayed on a computer-driven display allows a human subject to maintain extended visual fixation upon the resulting dynamic stimulus. (google.com.au)
  • The fixation is presented upon the display and the stimulus is altered to allow resensitization of the subject's retina, thereby allowing prolonged visual fixation upon the resulting dynamic target. (google.com.au)
  • Attentional load and sensory competition in human vision: modulation of fMRI responses by load at fixation during task-irrelevant stimulation in the peripheral visual field. (psu.edu)
Colenbrander lab | Smith-Kettlewell