Resource Library

Glaucoma refers to a group of eye conditions that lead to damage to the optic nerve, the nerve that carries visual information from the eye to the brain.

In many cases, damage to the optic nerve is due to increased pressure in the eye, also known as intraocular pressure (IOP).

Watch this video about: Glaucoma

Open-angle glaucoma; Chronic glaucoma; Closed-angle glaucoma; Congenital glaucoma; Angle closure glaucoma

Glaucoma is the second most common cause of blindness in the United States. There are four major types of glaucoma:

• Open-angle (chronic) glaucoma
• Angle-closure (acute) glaucoma
• Congenital glaucoma
• Secondary glaucoma

The front part of the eye is filled with a clear fluid called aqueous humor. This fluid is always being made in the back of the eye. It leaves the eye through channels in the front of the eye in an area called the anterior chamber angle, or simply the angle.

Anything that slows or blocks the flow of this fluid out of the eye will cause pressure to build up in the eye. This pressure is called intraocular pressure (IOP). In most cases of glaucoma, this pressure is high and causes damage to the major nerve in the eye, called the optic nerve.

Open-angle (chronic) glaucoma is the most common type of glaucoma.

• The cause is unknown. An increase in eye pressure occurs slowly over time. The pressure pushes on the optic nerve and the retina at the back of the eye
• Open-angle glaucoma tends to run in families. Your risk is higher if you have a parent or grandparent with open-angle glaucoma. People of African descent are at particularly high risk for this disease

Angle-closure (acute) glaucoma occurs when the exit of the aqueous humor fluid is suddenly blocked. This causes a quick, severe, and painful rise in the pressure within the eye (intraocular pressure).

• Angle-closure glaucoma is an emergency. This is very different from open-angle glaucoma, which painlessly and slowly damages vision
• If you have had acute glaucoma in one eye, you are at risk for an attack in the second eye, and your doctor is likely to recommend preventive treatment
• Dilating eye drops and certain medications may trigger an acute glaucoma attack

Congenital glaucoma often runs in families (is hereditary).

• It is present at birth
• It results from the abnormal development of the fluid outflow channels in the eye

Secondary glaucoma is caused by:

• Drugs such as corticosteroids
• Eye diseases such as uveitis
• Systemic diseases

OPEN-ANGLE GLAUCOMA

• Most people have NO symptoms until they begin to lose vision
• Gradual loss of peripheral (side) vision (also called tunnel vision)

ANGLE-CLOSURE GLAUCOMA

• Symptoms may come and go at first, or steadily become worse
• Sudden, severe pain in one eye
• Decreased or cloudy vision
• Nausea and vomiting
• Rainbow-like halos around lights
• Red eye
• Eye feels swollen

CONGENITAL GLAUCOMA

• Symptoms are usually noticed when the child is a few months old
• Cloudiness of the front of the eye
• Enlargement of one eye or both eyes
• Red eye
• Sensitivity to light
• Tearing

An eye exam may be used to diagnose glaucoma. The doctor will need to examine the inside of the eye by looking through the pupil, often while the pupil is dilated. The doctor will usually perform a complete eye exam.

Checking the intraocular pressure alone (tonometry) is not enough to diagnose glaucoma because eye pressure changes. Pressure in the eye is normal in about 25% of people with glaucoma. This is called normal-tension glaucoma. There are other problems that cause optic nerve damage.

Tests to diagnose glaucoma include:

• Gonioscopy (use of a special lens to see the outflow channels of the angle)
• Tonometry test to measure eye pressure
• Optic nerve imaging (photographs of the inside of the eye)
• Pupillary reflex response
• Retinal examination
• Slit lamp examination
• Visual acuity
• Visual field measurement

Open-angle glaucoma:

With good care, most patients with open-angle glaucoma can manage their condition and will not lose vision, but the condition cannot be cured. It's important to carefully follow up with your doctor.

Angle-closure glaucoma:

Rapid diagnosis and treatment of an attack is key to saving your vision. Seek emergency care immediately if you have symptoms of an angle-closure attack.

Congenital glaucoma:

Early diagnosis and treatment is important. If surgery is done early enough, many patients will have no future problems.

Call your health care provider if you have severe eye pain or a sudden loss of vision, especially loss of peripheral vision.

Call for an appointment with your health care provider if you have risk factors for glaucoma and have not been screened for the condition.

There is no way to prevent open-angle glaucoma, but you can prevent vision loss from the condition. Early diagnosis and careful management are the keys to preventing vision loss.

Most people with open-angle glaucoma have no symptoms. Everyone over age 40 should have an eye examination at least once every 5 years, and more often if in a high-risk group. Those in high-risk groups include people with a family history of open-angle glaucoma and people of African heritage.

People at high risk for acute glaucoma may opt to undergo iridotomy before having an attack. Patients who have had an acute episode in the past may have the procedure to prevent a recurrence.

Burr JM, Mowatt G, Hernández R, Siddiqui MA, Cook J, Lourenco T, et al. The clinical effectiveness and cost-effectiveness of screening for open angle glaucoma: a systematic review and economic evaluation. Health Technol Assess. 2007 Oct;11(41):iii-iv, ix-x, 1-190.

Kwon YH, Figert JH, Kuehn MH, Alward WL. Primary open-angle glaucoma. N Engl J Med. 2009 Mar 12;360(11):1113-24.

Vass C, Hirn C, Sycha T, Findl O, Bauer P, Schmetterer L. Medical interventions for primary open angle glaucoma and ocular hypertension. Cochrane Database Syst Rev. 2007 Oct 17;(4):CD003167.