Pharmacological and environmental factors in primary angle-closure glaucoma

A large number of drug classes have now been reported to provoke angle closure in high-risk individuals. The mechanism of action can be generalized into three main categories: sympathomimetic, parasympatholytic and idiosyndratic reactions. This review of the ophthalmic literature provides a clinical summary of primary angle-closure glaucoma (PACG) and its management. External stimuli (pharmacological and environmental) may induce acute, and more often, asymptomatic angle closure, which carries a significant risk of glaucoma. Whenever in doubt, patients at risk of PACG who are starting on drug therapy known to provoke angle closure or aggravate the condition should be referred for detailed gonioscopic examination of the anterior chamber by an ophthalmologist. The use of new imaging methods such as anterior segment optical coherence tomography to assess the presence or risk of angle closure is gaining popularity, and may offer a more rapid method of identifying people who are at risk of sight loss from angle-closure glaucoma precipitated by non-ophthalmological medication.