The Vestibuloocular System

Abstract

An important role of the vestibular system is to maintain stabilization of the visual image on the retina during head movement by means of vestibuloocular reflexes. Essentially these reflexes produce compensatory rotational eye movements relative to the skull in the same plane as, but in a direction opposite to, the plane of head rotation relative to space. For example, during downward tilting of the head compensatory eye rotation deviates the pupil of the forward-looking eye upward; horizontal head rotation to the left deviates the eyes to the right; head rotation about a fore-aft axis produces “counter rolling” of the eyes about parallel for-aft axes. Geometric and spatial attributes of these reflexes are elaborated elsewhere. Prolonged stimulation of the labyrinth, natural or electrical, leads to intermittent saccadic repositioning of the eyes which allows repetitive compensatory movements known as nystagmus to occur.