Nystagmus

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nystagmus

[nə′stag·məs]
(medicine)
Involuntary oscillatory movement of the eyeballs.

Nystagmus

 

an involuntary, rapid rhythmic oscillation of the eyeballs. The bilateral form of nystagmus is much more common than the unilateral form. Nystagmus can be lateral, rotatory, vertical, or diagonal, depending on the direction of the oscillations of the eyeball. The condition need not be pathological. For example, rotatory nystagmus can be induced in healthy persons who are revolving in a swivel chair, optokinetic nystagmus can result from fixing the eyes on moving objects, and caloric nystagmus can result when cold or warm water is poured into the ear.

Nystagmus is pathological when it results from a morbid condition in the vestibulocochlear nerve, in the vestibular nuclei of the brainstem, or in the labyrinth of the vestibular apparatus. Nystagmus can also result from a morbid process in the cerebellum, an inflammation of the inner ear, cerebrocranial traumas, infections and toxicoses of the brain, or neoplasms in the brain. In rarer cases, nystagmus is caused by eye diseases. Miner’s nystagmus is an occupational disease in miners who work with a pick under poorly illuminated and poorly ventilated conditions. Because these workers are constantly looking up or to the side, certain eye muscles become strained.

Nystagmus is treated by eliminating the underlying cause. In cases of miner’s nystagmus, the worker is transferred to jobs above the ground.

REFERENCE

Tsimmerman, G. S. Klinicheskaia otonevrologiia. Moscow, 1952.

V. A. KARLOV

References in periodicals archive ?
She was confused with gaze-evoked nystagmus and bilateral abducens nerve palsies, was areflexic with mildly reduced power and limb dysdiadochokinesia, and could not sit because of severe truncal ataxia.
In a recent study of oculomotor function in thirty patients with MSA, (8) excessive square-wave jerks were observed in 21 of the patients, a mild supranuclear gaze palsy in eight patients, a gaze-evoked nystagmus in 12 patients, a positioning down-beat nystagmus in 10 out of 25 patients, mild-moderate saccadic hypometria in 22 patients, impaired smooth pursuit movements in 28 patients, and reduced vestibulo-ocular reflex (VOR) suppression in 16 out of 24 patients.