hemianopia
Pronunciation: hem-ee-an-OH-pee-ah
Loss of vision in half of the visual field, typically indicating a lesion in the visual pathway posterior to the optic chiasm.
Full Definition
Hemianopia refers to loss of vision in one half of the visual field, either horizontally or vertically. Homonymous hemianopia affects the same side of the visual field in both eyes and indicates a retrochiasmal lesion in the optic tract, lateral geniculate nucleus, optic radiations, or visual cortex. Bitemporal hemianopia affects the outer halves of both visual fields and suggests a chiasmal lesion. The precise pattern of visual field loss helps localize the anatomical site of pathology and guide appropriate neuroimaging and management.
Usage
Usage note: Always specify whether hemianopia is homonymous or bitemporal, as this indicates different anatomical locations.
In Context
- "The patient exhibited a complete right homonymous hemianopia following left middle cerebral artery stroke." — Neurological assessment
- "Bitemporal hemianopia with superior field defects suggested a pituitary adenoma compressing the optic chiasm." — Endocrinology referral