Hippus

Hippus

Hippus is excessive pupillary unrest, i.e., rhythmic, oscillatory, contraction and dilatation of the pupil. It may reflect an imbalance between afferent pupillary sympathetic and parasympathetic autonomic activity. Hippus may be a normal phenomenon; it may be observed during recovery from an oculomotor (III) nerve palsy, but otherwise is of no localizing significance.