by Scholten A
(Acute Angle-closure Glaucoma; Single Angle-closure Glaucoma; Narrow Angle Glaucoma)


Glaucoma is an eye disease that can damage the eye nerve. Damage to the nerve can lead to poor eyesight or blindness. Angle-closure glaucoma (ACG) is one type of glaucoma. It may be:

  • Acute—a sudden and severe rise in pressure
  • Chronic—a slower rise in pressure over time
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ACG happens when fluid cannot drain from channels in the front of the eye. When fluid builds up, it raises pressure in the eye. This can damage the eye nerve.

ACG may be caused by:

  • Structural problems in the eye
  • Conditions that push or pull the iris (colored part of the eye) forward
  • Conditions that thicken the lens of the eye

Risk Factors

ACG is more common in women and adults over 50 years old. It is also more common in people of Chinese, Vietnamese, Pakistani, or Inuit decent. Other things that may raise the risk of ACG are:

  • Previous angle closure
  • A family history of angle closure
  • Farsightedness—problems seeing up close
  • Narrow drainage channels in the eye

In people at risk for ACG, the risk may be higher if they:

  • Take certain medicines, such as:
    • Eye drops to dilate the eyes
    • Adrenergics
    • Anticholinergics
    • Botulism injections around the eye
    • Sulfa-based drugs
    • Phenothiazines and monoamine oxidase inhibitors
    • Medicine to treat Parkinson disease
  • Walk into a dark room


Chronic ACG has few or no symptoms. Acute ACG may cause:

  • Severe pain in the eye
  • Sudden vision loss
  • Blurred or cloudy vision
  • Halo around lights
  • Headache
  • Redness and swelling of the eye
  • Nausea and/or vomiting

Acute ACG often happens in one eye at a time.

Chronic ACG may cause brief episodes of the symptoms above. The fluid channels may slowly get smaller in both eyes.


The doctor will ask about symptoms and health history. A physical exam may be done.

An eye doctor will give tests, such as:

  • Eye exam
  • Tonometry—to measure pressure in the eye
  • Slit-lamp examination—to check structures in the front of the eye
  • Gonioscopy—to check fluid channels of the eyes

Imaging of the retina may also be done, such as:

  • Nonmydriatic camera imaging
  • Optical coherence tomography

Other imaging and tests may be done, as needed.


Acute ACG needs care right away. The pressure will need to be lowered to prevent nerve damage. Fast treatment can help save vision.

Medicine can help lower pressure in the eye. It may be given as eye drops, pills, or through an IV.

Surgery can help widen the fluid channel in front of the eye. It is an option for chronic ACG or acute ACG once pressure is under control. Options include:

  • Laser peripheral iridotomy (LPI)—a hole is made in outer iris. It will increase open space for fluid to pass.
  • Lens extraction—the lens of the eye is removed. It will increase space for fluid. It may be used for people who also have cataracts.


Those at risk for ACG may be advised to not take certain medicines. Iridotomy may help lower the risk of ACG in those with narrow drain channels. This may be advised for those who:

  • Need to take medicines that put them at risk for ACG
  • Have had ACG symptoms
  • Cannot get fast eye treatment


The Glaucoma Foundation 

Glaucoma Research Foundation 


Glaucoma Research Society of Canada 

Canadian Ophthalmological Society 


Angle-closure glaucoma. American Academy of Ophthalmology website. Available at: . Accessed July 26, 2021.

Angle-closure glaucoma. EBSCO DynaMed website. Available at: Accessed July 26, 2021.

Angle-closure glaucoma. Glaucoma Research Foundation website. Available at: Accessed July 26, 2021.

Napier ML, Azuara-Blanco A. Changing patterns in treatment of angle closure glaucoma. Curr Opin Ophthalmol. 2018;29(2):130-134.

What is glaucoma? American Academy of Ophthalmology website. Available at: Accessed July 26, 2021.

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