Acute angle glaucoma (AACG) is an ocular emergency and receives distinction due to its acute presentation, need for immediate treatment, and well- established anatomic pathology. Rapid diagnosis, immediate intervention, and referral can have profound effects on patient outcome and morbidity. Immediate treatment is essential to prevent optic nerve damage and vision loss.

Acute angle closure occurs when intraocular pressure (IOP) rises rapidly as a result of sudden blockage of the trabecular meshwork by the iris. Angle closure may occur in two ways: (1) the iris may be pushed forward up against the trabecular meshwork or (2) the iris may be pulled up against the trabecular meshwork. In either case, the position of the iris causes the normally open anterior chamber angle to close. Aqueous humor that should normally drain out of the anterior chamber is trapped inside the eye, thereby increasing the IOP.