Glaucoma

What is glaucoma?

Glaucoma is an eye disease in which the nerve that connects the eye to the brain (optic nerve) is damaged. Usually, high pressure inside the eye causes the damage. The damage can lead to a loss of vision. However, early treatment can prevent blindness.

How does it occur?

A clear, watery fluid called the aqueous humor normally circulates in your eye. When the flow of this fluid out of the eye becomes blocked, the pressure increases inside the eye. The increased pressure can damage the optic nerve.

There are two main types of glaucoma, depending on how the flow of fluid is blocked:

Open-angle glaucoma is caused by a gradual blockage in the area that drains fluid from the eyes into the drainage channels. It is the more common type of glaucoma in the US and Europe. It usually affects both eyes.
Angle-closure glaucoma is a blockage caused by a change in the position of the iris (the colored part of the eye). The change in position causes the iris to block the drainage channels. This type of glaucoma usually happens in one eye at a time. If you get glaucoma in one eye, you are at risk for having the same problem in the other eye. When this type of glaucoma happens suddenly, it is called acute angle-closure glaucoma and is a medical emergency.

Glaucoma tends to run in families. It is a common eye problem in people over age 60. Open angle glaucoma is more common among black people than white people. However, angle-closure glaucoma is more common among Asian people than white people and rare in black people

What are the symptoms?

Open-angle and other chronic forms of glaucoma often have no symptoms in the early stages. In later stages, you will begin to notice a loss of vision. Side vision is affected first.

Symptoms of acute angle-closure glaucoma include:

severe eye pain
seeing halos around lights
nausea and vomiting
headache
loss of vision.

How is it diagnosed?

Your health care provider may screen you for vision problems during your routine checkups. If you have vision problems, your provider will refer you to an eye doctor.

The eye doctor may use the following tests to diagnose glaucoma:

tonometry, a painless procedure used to measure the pressure in your eyes
ophthalmoscopy, in which the doctor uses an instrument to look at the optic nerve inside your eye
visual field testing, which can show early changes in your side vision caused by damage to the optic nerve
gonioscopy, which is a method of examining the drainage channels.

How is it treated?

The goal in the treatment of glaucoma is to reduce the pressure in your eyes. This may be done with eyedrops, oral medication, laser surgery, or other types of surgery. Some eyedrops reduce the amount of fluid made by your eye. Others increase the amount of fluid that flows out. Surgery relieves pressure inside the eye by opening up the drainage channel or by making another opening through which the fluid can drain.

Make sure your health care provider tells you about possible side effects of any medication you are taking. If you have concerns, call your provider.

How long will the effects last?

Loss of vision caused by glaucoma is permanent. This is why glaucoma needs to be diagnosed and treated early to stop further damage to the optic nerve.

If your health care provider prescribes medication to control the pressure, you may need to take it for the rest of your life.

How can I take care of myself?

Take your medication as prescribed.
Carefully follow your health care provider's recommendations for follow-up visits and pressure measurements.
Call your health care provider if you have any side effects from your medication.

How can I help prevent glaucoma?

Glaucoma cannot be prevented. However, blindness can be prevented if glaucoma is treated before pressure in the eye has damaged the optic nerve too much.

You may be able to help prevent glaucoma from becoming severe if you:

Have a regular eye exam. How often you need to see the eye doctor will depend on how severely your optic nerve was damaged.
At your eye exam, make sure the pressure in your eye is measured and that your optic nerve is examined.
Learn about your family history. Chronic open-angle glaucoma often runs in families.
See your health care provider at once if you see halos around lights or notice any changes in your vision.

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.

HIA File EYE4216F.HTM Release 9.0/2006