Ipratropium-Induced Mydriasis

Pupillary abnormalities often evoke significant clinical concern, especially in ICU settings. We have observed cases of transient anisocoria among critically-ill patients who received nebulized bronchodilators via face mask. Though it is suspected that nebulized ipratropium could induce mydriasis if accidentally administered topically to the eye (23 case reports between 1986 and 2012 have described dilated pupils among patients using ipratropium inhalers and nebulizers) 1-23, only 3 studies have attempted to reproduce this anecdotal association.The use of topical pilocarpine 1% is considered a definitive diagnostic test to distinguish between pharmacological mydriasis and a third nerve palsy. We have, however, observed cases of presumed ipratropium-induced mydriasis at our institution in which the dilated pupil constricted when challenged with pilocarpine 1%. We suspect that ipratropium-induced mydriasis may be reversed by topical pilocarpine 1%, contradicting the widely-accepted anisocoria diagnostic algorithm.