Nystagmus - definition, causes and treatment

Nystagmus - definition, causes and treatment

Nystagmus - involuntary movements of the eyes, usually rapid and repetitive. Nystagmus can be congenital or acquired; in either circumstance it is a symptom of underlying disorders rather than itself a condition. Nystagmus nearly always indicates VISION IMPAIRMENT; if congenital, the impairment may improve or completely resolve with age. Vision impairment in adults depends on the underlying cause of the nystagmus. Temporary induced nystagmus, such as may occur with caloric testing (warm or cool water infused into the auditory canal) to assess disorders of the vestibular system, does not affect vision, although vestibular disorders can cause nystagmus.

Causes of Congenital NystagmusCauses of Acquired Nystagmus
ALBINISM (absence of retinal pigmentation)
congenital macular defects congenital CATARACT
absence of iris
anomalies of the OPTIC NERVE
vestibular disorders
brainstem or cerebellum damage or tumor
MULTIPLE SCLEROSIS
TRAUMATIC BRAIN INJURY(TBI)
chronic ALCOHOL abuse

The diagnostic path includes a comprehensive OPHTHALMIC EXAMINATION and NEUROLOGIC EXAMINATION. Treatment targets the underlying cause. Some adults who have acquired nystagmus receive relief from the muscle relaxant medication baclofen (Lioresal), which interrupts NERVE signals from the BRAIN to the muscles that control the eyes. The long-term consequences for vision depend on the cause and duration of the nystagmus. Occasionally nystagmus occurs as an undesired SIDE EFFECT of antiseizure medications, and typically goes away with switching to another medication.

See also BENIGN PAROXYSMAL POSITIONAL VERTIGO (BPPV); DIPLOPIA; MUSCLE RELAXANT MEDICATIONS; PHOTOPHOBIA; STRABISMUS.

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