Peripheral Visual Loss

Bilateral Hemianopia:

• Definition: Loss of the same visual field in both eyes.
• Causes: Often due to lesions in the optic chiasm or further back in the visual pathways.
• Types:
  • Bitemporal Hemianopia: Loss of the outer (temporal) halves of the visual field in both eyes, typically caused by a lesion at the optic chiasm (e.g., pituitary adenoma).
  • Binasal Hemianopia: Loss of the inner (nasal) halves of the visual field in both eyes, less common and often associated with lateral compression of the optic chiasm.

Total Blindness in One Eye:

• Definition: Complete loss of vision in one eye.
• Causes: Often due to damage to the optic nerve of the affected eye, such as optic neuritis, ischemic optic neuropathy, trauma, or severe retinal disease.

Right Incongruous Hemianopia:

• Definition: Partial loss of vision in the same field of both eyes (right side in this case), but the extent of loss is different (incongruous) between the two eyes.
• Causes: Typically indicates a lesion in the optic tract or lateral geniculate body, where the visual fields from both eyes overlap but not perfectly aligned.

Homonymous Superior Quadrantanopia:

• Definition: Loss of vision in the upper quarter of the same visual field in both eyes.
• Causes: Often caused by lesions in the temporal lobe affecting Meyer’s loop of the optic radiation, such as in temporal lobe tumors or strokes.

Homonymous Hemianopia:

• Definition: Loss of vision in the same half of the visual field in both eyes (either left or right).
• Causes: Commonly due to lesions in the optic tract, lateral geniculate nucleus, optic radiation, or occipital cortex. These lesions are typically due to stroke, trauma, or tumors.