Comparison of cholinergic supersensitivity in third nerve palsy and Adie's syndrome

Objective: To determine whether the degree of cholinergic supersensitivity of the pupil differs in patients with preganglionic injury of the oculomotor nerve (third nerve palsy) compared with patients with postganglionic injury (Adie's pupil). Methods: In this retrospective study, the authors first identified 11 patients with oculomotor nerve palsy and 11 patients with unilateral Adie's pupil who demonstrated supersensitive pupillary responses using dilute pilocarpine. The same methods for testing supersensitivity of the iris sphincter, and for defining its presence, had been used in both groups of patients. Pupil diameters of the affected and unaffected fellow eye were measured directly from self-developing photographs obtained before and 30 minutes after pilocarpine 0.1% was applied to both eyes. The amount of absolute constriction of the affected pupil, as well as the net constriction of the affected pupil (i.e., the amount of pilocarpine-induced constriction of the unaffected pupil subtracted from the amount of pilocarpine-induced constriction of the affected pupil), was compared between the two groups of patients using the Mann-Whitney test. Results: No significant differences were identified in any of the comparisons. Conclusions: The degree of cholinergic supersensitivity of the iris sphincter appears to be similar regardless of whether the site of injury along the parasympathetic pathway of the oculomotor nerve is preganglionic or postganglionic.