Optokinetic sensations evoked by local stimulation of the peripheral retina.
Optokinetic sensations of movement have been investigated by means of a moving pattern of stripes presented in the periphery of the visual field. Linear sensations of movement occur. The more peripheral in the visual field the pattern is presented, the more sensitive the retina becomes. Stimuli perpendicular to the horizontal meridian evoke stronger reactions than stimuli presented perpendicular to the vertical meridian. Vertically directed stimuli in the temporal field of vision give rise to more intense sensations than the same stimuli applied to the nasal field. An upward movement of stimulus pattern causes a more pronounced sensation of 'lift' than a downward movement. As for horizontal stimulation, sensations are more pronounced when stripes move from temporal to nasal than in the opposite direction. Only stimulation perpendicular to the meridian, either horizontal or vertical, induces sensations of movement. Stimulation in the same direction as these meridians, whether upward or downward for the vertical axis or to the left or the right for the horizontal axis, do not induce linear or circular vection. The results may be of importance in working with monitor screens. The differences between the method routinely used in optokinetic examination and the present stimulus method, are discussed.