The vestibulo-ocular reflex (VOR) is a reflex that acts to stabilize gaze during head movement, with eye movement due to activation of the vestibular system, it is also known as the cervico-ocular reflex. The reflex acts to stabilize images on the retinas of the eye during head movement. Gaze is held steadily on a location by producing eye movements in the direction opposite that of head movement. For example, when the head moves to the right, the eyes move to the left, meaning the image a person sees stays the same even though the head has turned. Since slight head movement is present all the time, VOR is necessary for stabilizing vision: people with an impaired reflex find it difficult to read using print, because the eyes do not stabilise during small head tremors, and also because damage to reflex can cause nystagmus.
The VOR does not depend on what is seen. It can also be activated by hot or cold stimulation of the inner ear, where the vestibular system sits, and works even in total darkness or when the eyes are closed. However, in the presence of light, the fixation reflex is also added to the movement. Most features of VOR are present in kittens raised in complete darkness.