Rhythmic pupillary oscillations accompanying a complete third-nerve palsy.

An automobile accident left a 26-year-old man in stupor with a complete right third-nerve palsy. Although fixed to light, the right pupil (only) exhibited continual concentric oscillations, initially at 1 Hz but slowing to 0.3 Hz during 2 weeks' observation. The pathophysiologic characteristics of this unique movement are uncertain but may involve central parasympathetic nervous system dysfunction.