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Retinal Correspondence
In visual perception, retinal correspondence is the inherent relationship between paired retinal visual cells in the two eyes. Images from one object stimulate both cells, which transmit the information to the brain, permitting a single visual impression localized in the same direction in space.Cassin, B. and Solomon, S. ''Dictionary of Eye Terminology.'' Gainesville, Florida: Triad Publishing Company, 1990. Types Normal retinal correspondence (NRC) is a binocular condition in which both foveas work together as corresponding retinal points, with resultant images fused in the occipital cortex of the brain. Abnormal retinal correspondence (ARC), also called ''Anomalous retinal correspondence'' is binocular sensory adaptation to compensate for a long-standing eye deviation (i.e. strabismus). The fovea of the straight (non-deviated) eye and non-foveal retinal point of the deviated eye work together, sometimes permitting single binocular vision. See also * Bagolini Striated Glass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Perception
Visual perception is the ability to detect light and use it to form an image of the surrounding Biophysical environment, environment. Photodetection without image formation is classified as ''light sensing''. In most vertebrates, visual perception can be enabled by photopic vision (daytime vision) or scotopic vision (night vision), with most vertebrates having both. Visual perception detects light (photons) in the visible spectrum reflected by objects in the environment or emitted by light sources. The light, visible range of light is defined by what is readily perceptible to humans, though the visual perception of non-humans often extends beyond the visual spectrum. The resulting perception is also known as vision, sight, or eyesight (adjectives ''visual'', ''optical'', and ''ocular'', respectively). The various physiological components involved in vision are referred to collectively as the visual system, and are the focus of much research in linguistics, psychology, cognitive s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retina
The retina (; or retinas) is the innermost, photosensitivity, light-sensitive layer of tissue (biology), tissue of the eye of most vertebrates and some Mollusca, molluscs. The optics of the eye create a focus (optics), focused two-dimensional image of the visual world on the retina, which then processes that image within the retina and sends nerve impulses along the optic nerve to the visual cortex to create visual perception. The retina serves a function which is in many ways analogous to that of the photographic film, film or image sensor in a camera. The neural retina consists of several layers of neurons interconnected by Chemical synapse, synapses and is supported by an outer layer of pigmented epithelial cells. The primary light-sensing cells in the retina are the photoreceptor cells, which are of two types: rod cell, rods and cone cell, cones. Rods function mainly in dim light and provide monochromatic vision. Cones function in well-lit conditions and are responsible fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Eye
The human eye is a sensory organ in the visual system that reacts to light, visible light allowing eyesight. Other functions include maintaining the circadian rhythm, and Balance (ability), keeping balance. The eye can be considered as a living optics, optical device. It is approximately spherical in shape, with its outer layers, such as the outermost, white part of the eye (the sclera) and one of its inner layers (the pigmented choroid) keeping the eye essentially stray light, light tight except on the eye's optic axis. In order, along the optic axis, the optical components consist of a first lens (the cornea, cornea—the clear part of the eye) that accounts for most of the optical power of the eye and accomplishes most of the Focus (optics), focusing of light from the outside world; then an aperture (the pupil) in a Diaphragm (optics), diaphragm (the Iris (anatomy), iris—the coloured part of the eye) that controls the amount of light entering the interior of the eye; then an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Brain
The human brain is the central organ (anatomy), organ of the nervous system, and with the spinal cord, comprises the central nervous system. It consists of the cerebrum, the brainstem and the cerebellum. The brain controls most of the activities of the human body, body, processing, integrating, and coordinating the information it receives from the sensory nervous system. The brain integrates sensory information and coordinates instructions sent to the rest of the body. The cerebrum, the largest part of the human brain, consists of two cerebral hemispheres. Each hemisphere has an inner core composed of white matter, and an outer surface – the cerebral cortex – composed of grey matter. The cortex has an outer layer, the neocortex, and an inner allocortex. The neocortex is made up of six Cerebral cortex#Layers of neocortex, neuronal layers, while the allocortex has three or four. Each hemisphere is divided into four lobes of the brain, lobes – the frontal lobe, frontal, pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fovea Centralis
The ''fovea centralis'' is a small, central pit composed of closely packed Cone cell, cones in the eye. It is located in the center of the ''macula lutea'' of the retina. The ''fovea'' is responsible for sharp central visual perception, vision (also called foveal vision), which is necessary in humans for activities for which visual detail is of primary importance, such as reading (activity), reading and driving. The fovea is surrounded by the ''parafovea'' belt and the ''perifovea'' outer region. The ''parafovea'' is the intermediate belt, where the Retinal ganglion cell, ganglion cell layer is composed of more than five layers of cells, as well as the highest density of cones; the ''perifovea'' is the outermost region where the ganglion cell layer contains two to four layers of cells, and is where visual acuity is below the optimum. The ''perifovea'' contains an even more diminished density of cones, having 12 per 100 micrometres versus 50 per 100 micrometres in the most centra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Cortex
The visual cortex of the brain is the area of the cerebral cortex that processes visual information. It is located in the occipital lobe. Sensory input originating from the eyes travels through the lateral geniculate nucleus in the thalamus and then reaches the visual cortex. The area of the visual cortex that receives the sensory input from the lateral geniculate nucleus is the primary visual cortex, also known as visual area 1 ( V1), Brodmann area 17, or the striate cortex. The extrastriate areas consist of visual areas 2, 3, 4, and 5 (also known as V2, V3, V4, and V5, or Brodmann area 18 and all Brodmann area 19). Both hemispheres of the brain include a visual cortex; the visual cortex in the left hemisphere receives signals from the right visual field, and the visual cortex in the right hemisphere receives signals from the left visual field. Introduction The primary visual cortex (V1) is located in and around the calcarine fissure in the occipital lobe. Each h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strabismus
Strabismus is an eye disorder in which the eyes do not properly align with each other when looking at an object. The eye that is pointed at an object can alternate. The condition may be present occasionally or constantly. If present during a large part of childhood, it may result in amblyopia, or lazy eyes, and loss of depth perception. If onset is during adulthood, it is more likely to result in diplopia, double vision. Strabismus can occur out of muscle dysfunction (e.g., myasthenia gravis), farsightedness, problems in the brain, trauma, or infections. Risk factors include premature birth, cerebral palsy, and a family history of the condition. Types include esotropia, where the eyes are crossed ("cross eyed"); exotropia, where the eyes diverge ("lazy eyed" or "wall eyed"); and hypertropia or hypotropia, where they are vertically misaligned. They can also be classified by whether the problem is present in all directions a person looks (comitant) or varies by direction (inco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bagolini Striated Glasses Test
The Bagolini striated glasses test, or BSGT, is a subjective clinical test to detect the presence or extent of binocular vision, binocular functions and is generally performed by an optometrist or orthoptist or ophthalmologist (medical/surgical eye doctor). It is mainly used in strabismus clinics. Through this test, suppression (eye), suppression, microtropia, diplopia and manifest deviations can be noted. However this test should always be used in conjunction with other clinical tests, such as Worth 4 dot test, Cover test, Prism Cover Test, Prism cover test and Maddox rod to come to a diagnosis. Equipment To perform the test you will need * Bagolini Striated Glasses * Pen torch or a distant light source. Alternatively, trial frames and lenses or a lorgnette can be used. In some cases, the use of Prism (optics), prisms is necessary to measure a deviation and test for the presence of binocular functions. Principles Apart from testing binocular vision, binocular functions, Bagol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binocular Vision
Binocular vision is seeing with two eyes. The Field_of_view, field of view that can be surveyed with two eyes is greater than with one eye. To the extent that the visual fields of the two eyes overlap, #Depth, binocular depth can be perceived. This allows objects to be recognized more quickly, camouflage to be detected, spatial relationships to be perceived more quickly and accurately (#Stereopsis, stereopsis) and perception to be less susceptible to optical illusions, optical illusions. In secion #Medical, Medical attention is paid to the occurrence, defects and sharpness of binocular vision. In section #Biological, Biological the occurrence of binocular vision in animals is described. Geometric terms When the left eye (LE) and the right eye (RE) observe two objects X and Y, the following concepts are important:Krol J.D.(1982),"Perceptual ghosts in stereopsis, a ghosly problem in binocular vision", PhD thesis ISBN 90-9000382-7.Koenderink J.J.;van Doorn A.J. (1976) "Geometry of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haploscope
A haploscope is an optical device for presenting one image to one eye and another image to the other eye. The word derives from two Greek roots: ''haploieides'', single and ''skopeo'', to view. The word is often used interchangeably with stereoscope, but it is more general than that. A stereoscope is a type of haploscope, but not vice versa. The word has more currency in the medical field than elsewhere, where it refers to instruments designed to test binocular vision. These instruments include Worth's amblyoscope and the synoptophore. Commonly haploscopes employ front-surfaced mirrors placed at different angles close to the eyes to reflect the images into the eyes. Reputedly the largest haploscope, with images of over a meter (in fact, 4 feet) square and a viewing distance for each eye of nearly five meters (16 feet), was constructed by Vaegan in about 1975 to research stereoacuity. The large images allowed very small retinal disparities to be presented. See also * Cheir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereopsis
Binocular vision is seeing with two eyes, which increases the size of the Visual field, visual field. If the visual fields of the two eyes overlap, binocular #Depth, depth can be seen. This allows objects to be recognized more quickly, camouflage to be detected, spatial relationships to be perceived more quickly and accurately(#Stereopsis, stereopsis) and perception to be less susceptible to optical illusions, optical illusions. In #Medical, medical attention is paid to the occurrence, defects and sharpness of binocular vision. In #Biological, biological the occurrence of binocular vision in animals is described. Geometric terms When the left eye (LE) and the right eye (RE) observe two objects X and Y, the following concepts are important: Egocentric distance The ''egocentric distance'' to object X is the distance from the observer to X. In the figure: Dx. Metric depth The ''metric depth'' between two objects X and Y is the difference of the egocentric distances to X and Y. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthoptist
Orthoptics is a profession allied to the eye care profession. Orthoptists are the experts in diagnosing and treating defects in eye movements and problems with how the eyes work together, called binocular vision. These can be caused by issues with the muscles around the eyes or defects in the nerves enabling the brain to communicate with the eyes. Orthoptists are responsible for the diagnosis and non-surgical management of strabismus (cross-eyed), amblyopia (lazy eye) and eye movement disorders.International Orthoptic Association document "professional role" The word ''orthoptics'' comes from the Greek words ὀρθός ''orthos'', "straight" and ὀπτικός ''optikοs'', "relating to sight" and much of the practice of orthoptists concerns disorders of binocular vision and defects of eye movement. Orthoptists are trained professionals who specialize in orthoptic treatment, such as eye patches, eye exercises, prisms or glasses. They commonly work with paediatric patients and al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
