Congenital Oculomotor Nerve Paresis With Isolated Cyclic Pupillary Spasms

Cyclic oculomotor nerve paresis is a rare and usually congenital disorder. It is characterized by unilateral third nerve paresis with periodic spasms causing eyelid elevation, miosis, and contraction of 1 or more of the extraocular muscles innervated by the third nerve. We report a 20-month-old girl who presented initially with a congenital partial right third nerve paresis without ptosis. She subsequently developed isolated cyclic spasms of the pupil followed several months later by permanent partial ptosis.