hippus means pupillary athetosis; spasmodic dilation and contraction of the pupil between the sphincter and dilator muscles.
Etymology
From Ancient Greek ἵππος (híppos, “horse”), perhaps due to the rhythm of the contractions representing a galloping horse.
noun
- pupillary athetosis; spasmodic dilation and contraction of the pupil between the sphincter and dilator muscles.