Optokinetic response

A reflexive eye movement induced by moving visual stimuli

Optokinetic response

The optokinetic response (OKR) is a reflexive eye movement that occurs when a large portion of the visual field moves rapidly. This response helps stabilize the image on the retina during head movements or when the visual environment is in motion. The optokinetic response is crucial for maintaining visual stability and is an important component of the vestibulo-ocular reflex (VOR).

Optokinetic nystagmus in response to moving stripes

Mechanism

The optokinetic response is initiated when the retina detects motion in the visual field. This motion is processed by the visual cortex and relayed to the brainstem, where it triggers eye movements that follow the direction of the moving stimulus. The response consists of two phases: a slow phase, where the eyes smoothly track the moving object, and a fast phase, where the eyes quickly reset to a new position to continue tracking.

Optokinetic nystagmus

Optokinetic nystagmus (OKN) is a specific type of optokinetic response characterized by alternating slow and fast phases of eye movement. It is commonly observed when a person watches a series of moving stripes or a rotating drum. The slow phase involves smooth pursuit of the moving stripes, while the fast phase involves a quick saccade in the opposite direction to reset the eye position.

Clinical significance

The optokinetic response is used clinically to assess the integrity of the visual and vestibular systems. Abnormalities in the optokinetic response can indicate issues with the central nervous system, such as lesions in the brainstem or cerebellum. Testing the optokinetic response can help diagnose conditions like nystagmus, vertigo, and other balance disorders.

Related pages

• Vestibulo-ocular reflex
• Nystagmus
• Visual cortex
• Retina