See through different eyes
What Field loss (hemianopia) looks like
Half of the visual field is missing
≈1 in 3 stroke survivors · NEI · Learn more
What it is
Loss of the same half of the visual field in both eyes, caused by damage to the visual pathway inside the brain rather than to the eyes. Because the two halves of the field are processed on opposite sides of the brain, damage on one side removes the opposite half of vision in both eyes at once.
What it looks like day to day
Half the world is simply not there, and crucially it does not appear as darkness: there is no edge to notice, in the same way you do not notice an edge behind your head. People bump into door frames on one side, read only half a line, leave food on one side of a plate, and may not be aware anything is missing.
What helps
Scanning training, which is the deliberate habit of turning the head toward the missing side, is the main rehabilitation approach. Prism lenses shift part of the missing field into view for some people. Some recovery can occur in the months after the causing event.
Who it affects
About one in three stroke survivors. It also follows brain injury and tumours affecting the visual pathway, and is usually sudden in onset rather than gradual.
Related conditions
Explore every condition or learn about color blindness.
This is an approximation, not a medical diagnosis.