Hemianopia
Hemianopia
Hemianopia (pronounced hee-mee-uh-NOH-pee-uh), also known as hemianopsia, is a type of visual field loss that results in blindness in half of the visual field. It is often caused by stroke, brain tumor, or trauma to the brain.
Etymology
The term "hemianopia" comes from the Greek words "hemi" meaning "half", "an" meaning "without", and "opsia" meaning "seeing". Thus, it literally translates to "half without seeing".
Types of Hemianopia
There are several types of hemianopia, including:
- Homonymous hemianopia: This is the most common type of hemianopia, where the same half of the visual field is lost in both eyes. It is often caused by damage to the optic tract, lateral geniculate nucleus, or the visual cortex.
- Binasal hemianopia: This type involves loss of vision in the inner or nasal half of the visual field in both eyes. It is often caused by compression of the optic chiasm.
- Bitemporal hemianopia: This type involves loss of vision in the outer or temporal half of the visual field in both eyes. It is often caused by a lesion at the optic chiasm.
- Quadrantanopia: This is a type of hemianopia where a quarter of the visual field is lost. It can be either homonymous or heteronymous, depending on whether the same or different quadrants are affected in each eye.
Treatment
Treatment for hemianopia depends on the underlying cause. In some cases, the condition may improve over time without treatment. In other cases, treatment may involve surgery, medication, or vision therapy.
Related Terms
- Visual field
- Visual cortex
- Optic chiasm
- Optic tract
- Lateral geniculate nucleus
- Stroke
- Brain tumor
- Trauma
External links
- Medical encyclopedia article on Hemianopia
- Wikipedia's article - Hemianopia
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