Anisocoria

Anisocoria is a visible inequality in pupil diameter. It is most often physiologic, usually with a difference in pupil size of less than 1 mm. Anisocoria can also be caused by neurologic disorders, uveitis, drugs, and structural abnormalities in the iris.

Image courtesy of Professor H.J. Meyer via the Online Journal of Ophthalmology (www.onjoph.com).