(n)small involuntary tremors of the eyeballs; when it is eliminated by stabilizing the image on the retina, visual perception fades rapidly from fatigue of the retinal receptors
(n)nystagmus caused by suddenly stopping the rapid rotation of the body; large slow movements of the eyeballs are in the direction opposite to the direction of rotation
‖n. [ NL., fr. Gr. &unr_; drowsiness, fr. &unr_; to nod in sleep, to slumber. ] (Med.) A rapid involuntary oscillation of the eyeballs. [ 1913 Webster ]