nystagmus
Pronunciation: nis-TAG-mus
Involuntary rhythmic oscillation of the eyes that can indicate neurological or vestibular pathology.
Full Definition
Nystagmus refers to involuntary, rhythmic movements of the eyes that can be horizontal, vertical, rotatory, or mixed. In neuro-ophthalmology, nystagmus often indicates dysfunction of the vestibular system, brainstem, or cerebellum. It can be physiological (such as optokinetic nystagmus) or pathological, and may be congenital or acquired. The pattern, direction, and associated symptoms help localize the underlying neurological lesion. Documentation should include the type of nystagmus, direction of fast phase, and conditions under which it appears or disappears.
Usage
Usage note: Always specify the type and direction of nystagmus in clinical documentation.
In Context
- "The patient demonstrated horizontal nystagmus that increased in intensity with leftward gaze." — Neurology examination
- "Acquired vertical nystagmus raised suspicion for a posterior fossa lesion." — Neuro-ophthalmology consultation