Postural disturbances due to homonymous hemianopic visual ataxia.

Patients with visual defects often complain of disturbances of equilibrium. In order to measure the influence of visual stimulation on posture, a study was made comparing the posture of hemianopic patients with that of healthy volunteers before and after occlusion of half of the monocular visual field. Hemianopia increases lateral oscillations in patients in the standing position and the projection of the body's centre of gravity shifts towards the hemianopia: in the volunteers, the same shift is noted after masking half the visual field. A tonic effect of visual information is discussed.