Tonic pupil and Czarnecki's sign following third nerve palsy.

A 71-year-old woman developed abnormal pupillary function in one eye after a third nerve palsy. Stimulation with light caused segmental constriction of the pupil, the near reflex was normal, and gaze upward elicited constriction of portions of the sphincter that were unreactive to light. This combination of findings has not been reported previously. We believe that this case supports the idea that a tonic pupil can be caused by aberrant reinnervation of the ciliary ganglion.