Complete loss or diminishment of vision in half of the visual field, typically in both eyes on the same side.
From Greek hemi- (half) + -opsia (condition of sight, from opsis meaning 'vision'), a medical term for visual field loss.
Hemiopsia is so invisible that stroke patients often deny it exists—they'll confidently insist they can see everything, not realizing an entire half of their world has vanished because their brain doesn't register the missing information.
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