Nystagmus Support Group

Nystagmus is rapid involuntary rhythmic eye movement, with the eyes moving quickly in one direction (quick phase), and then slowly in the other (slow phase). The direction of nystagmus is defined by the direction of its quick phase (e.g., right nystagmus is due to a right moving quick phase). Nystagmus may occur in the vertical or horizontal directions, and also in a semicircular movement, and thus are called downbeat nystagmus, upbeat nystagmus, seesaw nystagmus, periodic alternating nystagmus, and pendular nystagmus. There are other similar alterations in periodic eye movements (saccadic oscillations) such as opsoclonus or ocular flutter. One can accurately think of nystagmus as the combination of a slow adjusting eye movement (slow phase) like would be seen with the vestibulo-ocular reflex, followed by a quick saccade (quick phase) when the eye has reached the limit of its rotation.

Nystagmus is a relatively common clinical condition, affecting one in every 5,000 to 10,000 individuals. The cause for pathological nystagmus may be congenital, idiopathic, secondary to a pre-existing neurological disorder or may be induced temporarily by certain drugs (alcohol and other central nervous system depressants and stimulants, such as lithium salts, dilantin and ecstasy). Nystagmus generally causes a degree of vision impairment, although the severity of such impairment varies widely.

Pathological acquired nystagmus is mostly a temporary condition and stops spontaneously. When it is secondary to a neurological disorder, this must be treated accordingly. Congenital nystagmus is usually non-treatable, but several therapeutic approaches, such as contact lenses, drugs, surgery, and low vision rehabilitation can be used in order to improve visual function.