Demonstration of the hemiopic border in the normal person

The hemiopic border is the vertical line in the visual field separating the two halves which represent each cerebral hemisphere. This border, which becomes clinically manifest in the hemiopias, may be demonstrated in the normal person either (1) by covering an eye with the palm of the hand while facing the sun with the eyes closed, or (2) by fixing a near point and observing the background while the two eyes are dissociated by red and green glasses, or (3) by two-object perimetry, in which an inhibition may be observed along the vertical median through the fixation point.