What does homonymous hemianopia mean and how does it help localise the lesion?
Homonymous - same side of both eyes Hemi - half Anopia - loss of vision
There are many types of visual field defects and they can point towards the location of the lesion as well. One of these is hemianopia. It is the visual defect in which one half of the vision on vertical side is lost. It can be unilateral or bilateral. In the normal visual pathway right sided nerve fibers carrying stimulus travel to left side and left sided travel to right side. When we say homonymous hemianopia we mean that half of the vision of same side (meaning right or left) of both side has been lost. The condition may present as mobility issues as they bump into things a lot. Causes include: congenital, stroke, trauma, tumor, infection or as a post-surgical complication. Lesions from optic tract ending in visual cortex may also result in contralateral homonymous hemianopia. It is usually diagnosed with evidence of a lesion on CT scan or MRI for secondary issues like post cerebral artery occlusion (memory loss). Management is done by Field fixers/ prisms which help bend light and expand vision stimulus.
