Glaucoma · Patient Q&A

What is acute angle closure glaucoma?

Medically reviewed by Carl J. May Jr., MD · American Board of OphthalmologyReviewed July 9, 2026
If this is a medical emergency, call 911 or go to the nearest emergency room. For urgent eye symptoms during office hours, call May Eye Care Center at (717) 637-1919. When is it an eye emergency? →
Direct answer

Acute angle-closure glaucoma is a true eye emergency. The iris bows forward and seals the eye’s drainage angle, and pressure spikes within hours — causing severe eye pain, headache, blurred vision, halos around lights, a red eye, and often nausea or vomiting. Untreated, it can permanently damage the optic nerve within a day. If you have these symptoms, call us immediately at (717) 637-1919 — or go straight to the nearest emergency room after hours. Treatment with pressure-lowering medicines and a laser iridotomy is very effective when started quickly.

§Read video transcript

In cases of acute angle closure glaucoma, the iris may bow forward so much that it cuts off your eye's angle completely. Unlike narrow angle glaucoma, where some fluid can still drain from the eye, acute angle closure glaucoma does not let any fluid drain. It develops quickly, and its symptoms can include severe pain, red eye and nausea. acute angle closure glaucoma is a medical emergency. If the high pressure is not reduced within hours, it can permanently damage your vision. If you experience any of its symptoms, you should immediately contact your eye doctor or go to a hospital emergency room.

Medical sources

This page and video are for general patient education and are not a substitute for a medical examination, diagnosis, or treatment. Eye conditions vary by individual. For advice about your eyes, schedule an evaluation with May Eye Care Center. In an emergency, call 911.

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