Narrow Angle Glaucoma: Causes, Symptoms, Diagnosis & Treatment

Narrow angle glaucoma is a less common type of glaucoma. What is glaucoma? Glaucoma is a group of eye conditions that damage the optic nerve, often because pressure inside the eye is too high. That pressure is called intraocular pressure. The optic nerve carries images from the eye to the brain.

When intraocular pressure stays high, it can damage the optic nerve over time. Glaucoma is a leading cause of blindness in older adults, and vision lost to it cannot be restored.

It gets worse with time, and it can run in families. Most people with the common form of glaucoma have no symptoms or pain early on. The National Eye Institute says about half of people with glaucoma don’t know they have it. That is why regular dilated eye exams matter as you get older.

Types of Glaucoma

There are two types of glaucoma

1- Open-angle glaucoma

It is the most common type of glaucoma in the United States. The eye’s drainage angle looks open, but fluid drains too slowly and pressure builds gradually.

2- Closed-angle glaucoma

Narrow angle glaucoma, also called angle-closure glaucoma, happens when the drainage angle of the eye gets blocked. It can come on suddenly (acute) or slowly (chronic). A sudden attack causes a rapid rise in eye pressure and is a medical emergency.

What Are The Causes Of Narrow Angle Glaucoma?

The iris is the colored part of the eye that surrounds the pupil. In narrow angle glaucoma, the iris bows forward or bunches up and narrows the space between the clear cornea and the iris. This space is the drainage angle. When it closes, fluid can’t drain out and pressure inside the eye rises.

An attack can be triggered when the pupil widens, for example in a dark room. Some medicines that dilate the pupil can also trigger it in people with narrow angles.

Some Conditions are associated with narrow-angle glaucoma. That may include:

• Hyperopia

People who are farsighted are at higher risk because their eyes often have a shallow front chamber and narrow angles.

• Tumors

Rarely, a tumor or cyst behind the iris can push it forward and narrow the drainage angle.

• Cataract

As the lens of the eye thickens with age or a cataract, it can push the iris forward and crowd the angle.

Common Symptoms of Narrow Angle Glaucoma

When pressure rises suddenly because the drainage system is blocked, it can cause clear warning signs. The most common symptoms of acute angle-closure glaucoma may include: Severe eye pain or headache

• blurred vision
• Bloodshot Eyes
• Nausea, or vomiting
• Eye discomfort
• The appearance of rainbow-colored shadows around bright lights
• Sudden loss of vision in the affected eye

Symptoms of acute angle-closure glaucoma are obvious, and damage happens much faster than in open-angle glaucoma. The National Eye Institute says it can cause blindness within days. If you have these symptoms, go to an eye doctor or emergency room right away.

Risk Factors Associated With Narrow Angle Glaucoma

Following factors may be associated with the narrow angle glaucoma

• Age (risk rises after about age 50 to 60)
• Farsightedness
• Race (more common in people of East Asian descent)
• Cataract (a thicker lens can crowd the drainage angle)
• Sex (more common in women)
• Family history of angle-closure glaucoma

How Narrow Angle Glaucoma Can Be Diagnosed?

An eye doctor diagnoses it with a careful history and eye exam. They measure eye pressure and use gonioscopy, a special lens that shows whether the drainage angle is open, narrow or closed.

Many people with narrow angles never have an attack. An eye doctor can tell you whether preventive laser treatment makes sense for you.

Management of Narrow Angle Glaucoma

An acute attack needs emergency treatment. If you have symptoms, seek medical care right away. Treatment depends on the type of glaucoma, how advanced it is and your overall health.

1. Medication

First, doctors usually give eye drops, and sometimes pills or IV medicine, to lower eye pressure quickly. Some drops, such as pilocarpine, shrink the pupil to pull the iris away from the drainage angle. Medicine is a temporary fix; the main treatment is a laser iridotomy.

2. Laser Iridotomy

In this procedure, a laser makes a tiny opening in the iris. This gives fluid another path to flow from behind the iris to the front of the eye, which lets the iris fall back and opens the angle.

Doctors often treat the other eye too, because it is at risk of a future attack.

With these measures, intraocular pressure falls and symptoms begin to ease. Fast treatment can prevent or limit vision loss, but any vision already lost cannot be restored. Without treatment, it may lead to permanent vision loss or blindness.

Sources

• Glaucoma, National Eye Institute
• Types of Glaucoma, National Eye Institute
• What Is Angle-Closure Glaucoma?, Glaucoma Research Foundation