Updated on 

April 5, 2022

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Narrow-Angle Glaucoma

What is Narrow-Angle Glaucoma?

Narrow-angle glaucoma is one type of glaucoma. Glaucoma includes a range of eye conditions in which the optic nerve is damaged, endangering your vision.

High intraocular pressure is the most common cause of optic nerve damage. 

Narrow-angle glaucoma is when your iris protrudes forward and blocks the drainage angle between your cornea and iris.

When fluid cannot move around the eye properly, pressure builds up. The pressure increases your risk of optic nerve damage and permanent vision loss. 

Narrow-angle glaucoma is also called closed-angle glaucoma or angle-closure glaucoma

Narrow-angle glaucoma can be either acute or chronic.

Acute Narrow Angle Glaucoma

Acute narrow-angle glaucoma is a sudden and severe onset of blockage. The symptoms are quite painful.

It is considered a medical emergency and requires immediate medical attention. To prevent vision loss, contact an ophthalmologist or visit an emergency room as soon as possible.

Chronic Narrow-Angle Glaucoma

Chronic narrow-angle glaucoma is a gradual or partial closure of the drainage angle.

It is less dangerous than acute narrow-angle glaucoma, but it can also result in permanent vision loss.

Undergoing regular eye exams can help catch glaucoma in its early stages. If they detect it early, your eye doctor may be able to slow or prevent vision loss. 

Stages and Types of Narrow-Angle Glaucoma

There are 3 stages to describe narrow-angle glaucoma:

  • Primary angle closure suspect
  • Primary angle closure
  • Primary angle closure glaucoma

Narrow-angle glaucoma can present any of the following types:

  • Latent — No symptoms are present
  • Subacute — Mild symptoms are presented but resolve on their own
  • Acute — Sudden and severe onset of symptoms
  • Chronic — Persistent, gradual progression of symptoms
  • Absolute — Irreversible vision loss has occurred

Symptoms of Narrow-Angle Glaucoma 

Chronic angle-closure glaucoma will not have symptoms until the condition has reached a certain level of severity.

If a person experiences an acute attack, symptoms will be severe and occur suddenly. 

People with the following symptoms should speak with an ophthalmologist or visit an ER immediately:

  • Sudden blurred vision
  • Severe eye pain
  • Headache
  • Nausea
  • Vomiting 
  • Rainbow-colored rings or halos around lights

Glaucoma is a leading cause of blindness in people aged 60 and up.5 

— The Mayo Clinic

Potential Complications of Narrow-Angle Glaucoma

If you do not seek treatment for narrow-angle glaucoma, you are at risk of serious complications, including:

Permanent Visual Acuity Loss

People with narrow-angle glaucoma can lose visual acuity (sharpness).

In many cases, symptoms of this eye narrow-angle glaucoma are delayed. This can increase your likelihood of vision loss.

Regular comprehensive eye exams can help prevent this.

Central Retinal Artery Occlusion

Central retinal artery occlusion (CRAO) is when a vessel carrying blood to the eye’s retina becomes blocked.

This can happen without notice or pain and result in eyesight loss. Neovascular glaucoma can develop after a CRAO.

Malignant Glaucoma

This term refers to a rare but aggressive form of treatment-resistant postoperative glaucoma.

This condition causes increased intraocular pressure and a shallow or flat anterior chamber. 

In severe cases, it causes blindness.

Eye doctors may also use the following terms to describe this condition:

  • Ciliary block glaucoma
  • Aqueous misdirection syndrome
  • Direct lens-block glaucoma

Fellow Eye Attack

A "fellow eye" refers to the other eye where the condition is not present.

Symptoms in one eye could cause an attack or increased eye pressure in its fellow eye.

To minimize the likelihood of the event, an eye doctor may perform:

  • A prophylactic iridectomy (preventative partial removal of the iris)
  • Laser iridotomy (creates a hole in the outer edge of the iris)

How Common is this Form of Glaucoma? 

This form of glaucoma affects many people worldwide.

Approximately 15.7 million people suffer from primary angle-closure glaucoma.

Asian populations have an increased risk of this condition. 

Treatment can help manage glaucoma and prevent blindness in most cases.

However, even with care, approximately 15% of people with glaucoma lose complete vision in at least one eye within 20 years. 

Causes of Narrow-Angle Glaucoma

Causes of narrow-angle glaucoma include:

Pupillary Block

This is a primary cause of narrow-angle glaucoma. It occurs when the iris and lens come in contact. This obstructs the flow of aqueous into the anterior chamber.

Surgery may help relieve or prevent this blockage.

Posterior Pressure on the Iris

If there is pressure on the iris, it can come into contact with the trabecular meshwork. This tissue fluid drains aqueous fluid from the eye.

If this drainage is blocked, it can increase eye pressure.

Mature cataracts, lens dislocation, intraocular tumors, and swelling of the uvea (middle layer of the eye) can all put pressure on the iris.

Neovascularization

Iris and angle neovascularization is new, abnormal blood vessel growth.

Examples include diabetic retinopathy, retinal vascular occlusions, and ocular ischemia (restriction in blood supply).  

Medication Side Effects

Some prescription drugs may increase the risk for angle-closure, such as eye drops to dilate the pupils.

Who Is at Risk of Developing Narrow-Angle Glaucoma?

People with the following risk factors have an increased risk of this form of glaucoma:

  • High intraocular pressure 
  • Narrow drainage angles in eyes
  • Aged 60 or up
  • Being black, Asian, or Hispanic 
  • A family history of glaucoma
  • Have diabetes, heart disease, high blood pressure, or sickle cell anemia
  • Thin corneas
  • Extreme farsightedness
  • Eye injury
  • Certain eye surgeries
  • Taking corticosteroid medications for an extended period

Many people will develop narrow-angle glaucoma slowly and gradually. No symptoms are present until eye damage is severe or an acute attack occurs. 

Open-Angle vs. Narrow-Angle Glaucoma

There are different forms of glaucoma. Narrow-angle glaucoma and open-angle glaucoma are two examples.

Open-angle glaucoma is the most common form.

In these cases, the drainage angle remains open. The main issue is blockage of the trabecular meshwork.

As a result, eye pressure begins to go up. This increases the risk of optic nerve damage and vision loss. 

Symptoms of open-angle glaucoma include the following:

  • Patchy blind spots in peripheral or central vision (often in both eyes)
  • Tunnel vision (during advanced stages of the condition)

Unlike acute narrow-angle glaucoma, the onset of symptoms of open-angle glaucoma is slow.

Most people remain asymptomatic until the open-angle glaucoma is more advanced. Acute narrow-angle glaucoma can inflict damage to the optic nerve quickly.  

How is Narrow-Angle Glaucoma Diagnosed?

To diagnose narrow-angle glaucoma, your eye doctor will perform a thorough eye examination.

During the examination, they may use the following tests:

  • Measuring intraocular pressure (tonometry)
  • Assess optic nerve damage (dilated eye examination and imaging tests)
  • Examine areas of vision loss (visual field test)
  • Measure corneal thickness (pachymetry)
  • Examine the drainage angle (gonioscopy)

The American Academy of Ophthalmology (AAO) recommends an eye exam every 5 to 10 years for ages 40 and younger. They recommend people over 65 receive an eye exam every 1 to 2 years.

Frequent screening is necessary for those who are at risk of glaucoma.1 

Treatment Options for Narrow-Angle Glaucoma 

If you have narrow-angle glaucoma, treatment options are available.

Taking steps to improve your eye health can prevent or slow vision loss and damage to the optic nerve. 

Speak with your ophthalmologist immediately if you think you are at risk for glaucoma.

Treatment possibilities include:

Oral, Topical, or Intravenous Medications

These medical treatments are used on patients undergoing an acute attack. They are meant to provide relief until the patient can see an opthalmologist

Sometimes these will be enough to "break the attack" and are sufficient treatment.

Further treatment will try to resolve the underlying cause.

Peripheral Iridotomy

This surgery creates a hole in the iris. A laser will typically be used to make the hole.

It allows the aqueous to flow and relieves eye pressure.

Lensectomy (Cataract Surgery)

If a cataract is the underlying cause, your doctor may elect to remove the affected lens immediately.

Your ophthalmologist may recommend preventive surgery for the fellow eye as well.

Tips for Managing Narrow-Angle Glaucoma 

To prevent vision loss, follow the steps prescribed by your eye doctor. A

surgical procedure may be necessary to slow the onset of the eye condition. 

Other lifestyle changes to promote eye health include:

  • A healthy diet rich in zinc, copper, selenium, and antioxidant vitamins C, E, and A
  • Limiting caffeine intake 
  • Exercising regularly 
  • Sleeping with your head elevated at approximately 20 degrees
  • Integrating relaxation and meditation techniques 

Common Questions & Answers

How serious is narrow-angle glaucoma?

Narrow-angle glaucoma is a serious condition. If left untreated, it can cause permanent blindness. 

What should I avoid with narrow-angle glaucoma?

You should avoid antihistamines, decongestants, asthma medicine, motion sickness drugs, and tricyclic antidepressants.

Speak with your doctor beforehand about any changes in medication regimens. 

Can narrow-angle glaucoma be cured?

In some cases, treatment can create successful and long-lasting results. It is important to maintain check-ups, as a chronic form of glaucoma may still arise. 

Can you go blind from narrow-angle glaucoma?

Yes. If you do not receive proper care, especially after an acute attack, your risk of blindness increases. 

Can stress cause narrow-angle glaucoma?

Stress may affect intraocular pressure and influence the severity of the eye condition. However, more research is needed. 

You should integrate mindfulness and relaxation techniques to lower stress levels.

7 Cited Research Articles
  1. Boyd, K. (2021, June 15). What Is Glaucoma? American Academy of Ophthalmology.
  2. Cleveland Clinic. (2014, April 25). Case Studies: Cataract Surgery for Narrow-Angle Glaucoma. Consult QD.
  3. Flores-Sánchez, B. C. (2019, December 10). Acute angle closure glaucoma.
  4. Gillmann, K., Hoskens, K., & Mansouri, K. (2019, March 8). Acute emotional stress as a trigger for intraocular pressure elevation in Glaucoma. BMC Ophthalmology.
  5. Mayo Foundation for Medical Education and Research. (2020, October 23). Glaucoma. Mayo Clinic.
  6. Symptoms of Angle-Closure Glaucoma. Glaucoma Research Foundation. (n.d.).
  7. Varma, D., Adams, W. E., Phelan, P. S., & Fraser, S. G. (2006, May). Viscogonioplasty in patients with chronic narrow angle glaucoma. The British Journal of Ophthalmology.
Melody Huang is an optometrist and freelance health writer. Through her writing, Dr. Huang enjoys educating patients on how to lead healthier and happier lives. She also has an interest in Eastern medicine practices and learning about integrative medicine. When she’s not working, Dr. Huang loves reviewing new skin care products, trying interesting food recipes, or hanging with her adopted cats.
Anthony Armenta earned his B.A. in International Relations from the University of California, Irvine. After graduation, he decided to live abroad in Spain. Currently, he has spent the past 5 years working as a freelance health content writer and medical editor for different public hospitals in central Barcelona. He has covered different medical specialties from infectious diseases and pneumology to breast cancer and plastic surgery. His commitment to writing fact-driven, health-related content stems from the belief that such type of information can empower all individuals to take action and improve their health today.
https://www.visioncenter.org/author/anthony/
Author: Anthony Armenta  | UPDATED April 5, 2022
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Medical reviewer: Dr. Melody Huang, O.D.
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Dr. Melody Huang, O.D.
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The information provided on VisionCenter.org should not be used in place of actual information provided by a doctor or a specialist.

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