Walsh & Hoyt: Optokinetic Movements

Summary. Optokinetic smooth eye movements sustain compensatory eye speed at the same speed as the head during low-frequency or prolonged rotations. The VOR responds best to brief, higher-frequency changes in head position. The optokinetic system is the helpmate of the angular VOR in keeping the eyes still in space during low-frequency head motion. Optokinetic slow phases are induced reflexively by large scenes that stimulate much of the retina, whereas smooth pursuit is usually induced by a small moving object with its image located near the fovea. Optokinetic responses are naturally evoked during head motion with the environment stable but also occur with the head still and the visual scene in motion. Sequential slow phases and opposed quick phases represent optokinetic nystagmus (OKN).