Condition

Angle-Closure Glaucoma

Also known as Acute Angle-Closure Glaucoma, Narrow-Angle Glaucoma, Closed-Angle Glaucoma, Pupillary Block Glaucoma, AACG

Updated May 16, 2026For educational purposes only. Not a substitute for medical advice. See our terms.

Bottom Line

Angle-closure glaucoma happens when the iris blocks the eye's drain. A sudden attack with pain, halos, nausea, or vision loss is an emergency.

Angle-closure glaucoma starts when the drainage angle in the front of the eye becomes too narrow or closes. Fluid cannot leave the eye well, so eye pressure can rise 1.

Some people have narrow angles with no symptoms. Others have a sudden acute attack with severe pain, red eye, blurry vision, halos, headache, nausea, or vomiting 2.

Acute angle closure can damage vision quickly. Treatment lowers pressure and often uses a laser opening in the iris to help fluid move 3.

Symptoms and Warning Signs

Acute angle closure can cause:

  • Sudden severe eye pain. The pain is often in one eye.
  • Red eye. The eye may look very inflamed.
  • Blur or vision loss. Vision can drop quickly.
  • Halos around lights. Halos may come with headache.
  • Nausea or vomiting. Eye pressure can trigger whole-body symptoms.
  • Mid-sized pupil. The pupil may not react normally.
Go to the emergency room now if these symptoms start suddenly.

Acute angle-closure glaucoma is treated as an emergency because pressure can rise fast 3.

Diagnosis and Treatment

The key test is gonioscopy. The doctor uses a mirrored lens to see whether the drainage angle is open, narrow, or closed.

Treatment depends on the situation:

  • Pressure-lowering medicine. Drops and pills can lower pressure quickly.
  • Laser iridotomy. A tiny laser opening in the iris helps fluid move.
  • Cataract surgery. Removing a thick lens can deepen the angle in some eyes.
  • Long-term glaucoma care. Some eyes need drops or surgery after the attack.

Primary angle closure glaucoma management often aims to open the angle and prevent optic nerve damage 1.

Medicines and Triggers

Some medicines can dilate the pupil or narrow the angle in at-risk eyes. This includes some cold medicines, nausea medicines, bladder medicines, and mood medicines.

Do not stop prescribed medicine on your own. If you have been told you have narrow angles, ask your eye doctor which medicines are safe for you.

Dim rooms, stress, or pupil dilation at an exam can trigger symptoms in some narrow-angle eyes 2.

Common Questions About Angle-Closure Glaucoma

No. Narrow angles can be quiet for years. A sudden attack with pain, halos, nausea, or vision loss is an emergency.

Next Steps

  1. 1Go to the emergency room now for sudden severe eye pain, halos with nausea, vomiting, or vision loss.
  2. 2Ask your eye doctor whether your drainage angles are open or narrow.
  3. 3Tell every doctor if you have narrow angles or had angle closure.
  4. 4Ask before using new cold, allergy, bladder, or nausea medicines.
  5. 5Keep follow-up visits after laser or surgery.

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