Nystagmus is repetitive uncontrolled movement of the eyes that has various causes including vestibular disorders. Nystagmus associated with the vestibular system will be evident by a slow drift of the eyes in one direction and then a fast ‘jerk’ back towards the midline. Nystagmus due to vestibular dysfunction usually decreases with visual fixation (focusing the eyes on a target).

The direction and behaviour of nystagmus can provide vital information regarding the functioning of the vestibular system and the diagnosing of vestibular disorders.