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"What is Hippus?"

ZocdocAnswersWhat is Hippus?


My eyes are always dilated, much more than the average person's eyes. I read online that this can be a symptom of hippus, but I can't find a clear description of what hippus is or what it does. As a person who might have it, what should I know about hippus? Or should I just see a doctor?


Questions about health and one's eyes are best answered by an ophthalmologist. He or she can perform a detailed history and physical exam, including the use of special equipment to examine all parts of the eye. The condition called hippus is also called pupillary athetosis, or spasmodic, rhythmic dilation and constriction of the pupils. The condition is also characterized by the fact that this contraction and dilation of the pupil is rhythmic in nature but is also irregular. The name itself comes from the Greek word hippos which means horse, presumably because the movement of the pupil was thought to look like a galloping horse. In general, hippus is most noticable when a patient is having his or her pupils examined with a light. Of note, the pupillary changes themselves are generally independent of a light source. The condition itself is generally benign, but it can be associated with some medical conditions, including myasthenia gravis, neurosyphilis, multiple sclerosis, and poisoning with the compound aconite. As with any change noted in one's health, it is best to have a symptom like hippus evaluated by a physician. The changes in the eye may be the sign of a more serious illness but they could also be entirely benign.

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