眼球震顫
Nystagmus \Nys*tag"mus\, n. [NL., fr. Gr. ? drowsiness, fr. ? to nod in sleep, to slumber.] (Med.) A rapid involuntary oscillation of the eyeballs.
nystagmus n : involuntary movements of the eyeballs; the presence or absence of nystagmus is used to diagnose a variety of neurological and visual disorders