Pupillotonia in a dog.

A 5-year-old German Shepherd Dog was examined because of anisocoria. Pupillatonia because of parasympathetic denervation of iris sphincter muscle was diagnosed. This finding, most commonly referred to as Adie's tonic pupil in human medical literature, illustrated such a case in a species other than man. Diagnosis consisted of measuring the change in size of the pupillary aperture in response to topical administration of 0.1% pilocarpine. It is hoped that this report will help practitioners to be cognizant of pupillatonia when sorting out anisocorias.