Acute angle closure (AAC) is an ocular emergency requiring prompt identification and treatment to prevent permanent visual impairment. The sudden onset of marked ocular hypertension typically causes a cluster of well-known symptoms and signs, yet the condition can still be misdiagnosed or attributed to a nonophthalmologic cause. Even with appropriate treatment, approximately 1 in 11 cases may lead to blindness from glaucomatous optic neuropathy.1 Precipitating iatrogenic factors are identifiable in 40% of cases, including pupil dilation and the use of β-agonists and antidepressants, such as selective serotonin reuptake inhibitors and tricyclic antidepressants.2 The underlying mechanism behind AAC is the aqueous outflow obstruction due to iridotrabecular contact that causes an extreme increase in intraocular pressure, although what ultimately causes simple iridotrabecular contact to progress from a stable to an acute episode of increased pressure remains unclear.