cortical blindness

cortical blindness

n.

Loss of sight due to an organic lesion in the visual cortex.

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cortical blindness

[kôr′tikəl]

Etymology: L, cortex + AS, blind

loss of vision that results from a lesion in the visual center of the cerebral cortex of the brain.

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blindness

lack or loss of ability to see. Diagnosed in an animal on the absence of a menace reflex, walking into obstructions and failure to indicate awareness of a soundless movement in its visual field, e.g. a falling cotton ball or feather.

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Appaloosa night blindness

see appaloosa.

bright blindness

toxic retinopathy in sheep grazing bracken; characterized by blindness, dilated pupils, poor pupillary light reflex, retinal degeneration.

central blindness

due to a lesion of the optic cortex; the pupillary light reflex still functions. Called also cortical blindness.

cortical blindness

see central blindness (above).

day blindness

defective vision in bright light. See also hemeralopia.

inherited congenital blindness

occurs in a number of breeds of cattle in which there are several defects in the eyes including irideremia, microphakia, ectopia lentis and cataract.

night blindness

failure or imperfection of vision in conditions of diminished illumination; a characteristic of progressive retinal atrophy.

peripheral blindness

blindness due to a lesion in the optical apparatus peripheral to the optical cortex, including lesions in the optic chiasma, optic nerve, retina, anterior and posterior chambers, lens and cornea. With the exception of obvious lesions in the eyeball this is characterized by dilatation of the pupil and absence of the pupillary light reflex.