eye disorders
Unequal Pupils
Introduction
The pupil is the black center of the eye. Pupils get larger (dilate) in dim light and smaller (constrict) in bright light. Usually both pupils are about the same size and respond to light equally. Unequal pupil size is called anisocoria. If pupil sizes are very unequal, a person may notice the discrepancy. More often, unequal pupils are noticed only during a doctor's examination. Unequal pupils themselves usually cause no symptoms, but occasionally a person may have trouble focusing on near objects. Also, the underlying disorder sometimes causes other symptoms such as eye pain and redness, loss of vision, drooping eyelid, double vision, or headache. These more noticeable symptoms, rather than the unequal pupils, are often the reason people seek medical care. 