Homonymous hemianopia
Loss of half the visual field in both eyes, usually after a stroke or other brain injury affecting the visual cortex.
Try Homonymous hemianopia in the simulator →What it looks like
In homonymous hemianopia, the same half (left or right) of the visual field is missing in both eyes. The person can move their eyes and head to scan into the blind half, but without that effort the affected side simply isn't there — they bump into walls or door frames on that side, miss the start or end of lines while reading. Often, a small central island of vision is preserved (macular sparing), which lets the person continue to read and recognize faces using the central few degrees.
Why macular sparing is common
The tip of the occipital lobe — which processes the central part of vision — receives dual blood supply from both the posterior cerebral artery and end branches of the middle cerebral artery. So a single stroke often spares this region, leaving central vision intact even when the rest of one hemifield is lost.
Also known as
Hemianopia · Hemianopsia · Half-field visual loss