Hemianopia

A person suffering from this visual impairment will have lost one full half of their vision. This may be the left or right half, or the lower or (as shown here) the upper half. Vision is lost from both eyes, so that the person is not aware of any objects or action taking place in the impaired part. The picture simulates how this would appear. It shows a tenement block as it would be seen both by a normally sighted viewer, and by a person with hemianopia. The occluded part is missing, not merely darkened or fuzzy. Rather than the effect of a roller blind pulled half part way down a window, (which would at least enable the viewer to understand that something may be taking place behind the drawn portion) the picture shows how the remaining half of the field effectively fills the whole of the perceptual area, leaving the viewer unaware of any action in the upper stories of the building. Note that the most acute area of sight is offset toward the top of the view, where the retinal centre is.