Atlas of Ophthalmology

Tonic Pupil

Tonic Pupil
Top: This 29-year-old man reported that his right pupil had been dilated for six weeks. On direct light stimulation, the right pupil showed minimal reaction while that on the left reacted normally. Slit lamp examination revealed that the dysfunction of the iris sphincter muscle in the right eye was sectoral, with some segments retaining contractile ability and others showing complete paralysis. Eyelids and ocular motility were normal. Bottom: Following instillation of weak-strength (0.125%) pilocarpine into both eyes, the right pupil constricts to the point where it is smaller than the left pupil. The demonstration of this phenomenon, termed denervation supersensitivity, helps to confirm the diagnosis of tonic pupil. Unilateral or bilateral tonic pupils reflect damage to post-ganglionic parasympathetic fibers, either at the level of the ciliary ganglion or along the course of the short ciliary nerves.
Pollock, Stephen C. , M.D., ¦1, Mebane NC, USA
H57.0
Neuro-Ophthalmology -> Pupillary Abnormalities -> Neurogenic Disorders -> Tonic Pupil
5831
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