L12 Disorders of Vision

Flashcards about Disorders of Vision

Homonymous Hemianopia

Visual field loss on sides of both eyes, often resulting from damage to the optic tract or visual cortex.

Blindsight

The ability to localise moving visual stimuli without “seeing” them, because info reaches the dorsal stream, bypassing primary visual cortex (V1), and reaching V5 (detects visual stimulus))

Achromatopsia

the absence of color vision, typically resulting from damage to area V4 of the visual cortex or absence of cone photoreceptors (most common reason)

Akinetopsia

the inability to perceive motion, usually due to damage to area V5/MT of the visual cortex.

Visual Agnosia

impairment in the ability to recognize objects despite intact visual perception; the person can see the object but cannot name or understand it.

Apperceptive Agnosia

type of visual agnosia, the failure to recognize objects due to bilateral damage to V1. Can percieve colour and movement. Poor copy and matching abilities.

Peppery Mask Hypothesis

An explanation for apperceptive agnosia, suggesting that damage to V1 creates multiple blind spots (scotomas), they can see better when they move.

Dorsal Simultagnosia

A form of visual agnosia where a person can only perceive one object at a time due to bilateral damage to the parietal lobes. Spatial perceptual impairment.

Ventral Simultagnosia

A type of visual agnosia where a person can see multiple objects, but can only clearly recognize one at a time, damage to the ventral stream beyond V4. colour and motion perception intact.

Associative Agnosia

A visual agnosia where a person can copy drawings accurately but cannot recognize the object. It involves a disconnect between perception and object association or meaning.