The Vestibulo-Ovular Reflex

Each time we turn our heads, the vestibulo-ocular reflex (VOR) generates a smooth eye movement that is equal in amplitude and opposite in direction to the head movement. As a result, the eyes remain stationary with respect to the world, and the images from the stationary surroundings remain relatively stationary on the retina. It is extremely important for visual acuity that the VOR perform accurately. We are always turning our heads, either as part of an effort to look at a target, or involuntarily as we move through the world. Indeed, there are small head oscillations at all times, even if we attempt to hold our head still. If these head turns resulted in image motion across the retina at speeds of greater than 2 to 3 deg/s, visual acuity would be reduced.