Glaucoma

What is glaucoma?

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

How does it occur?

Normally, the fluid in the front of the eye (called the aqueous humor) flows from where it is formed (the ciliary body) to the front of the eye. The fluid drains from the angle (where the iris and cornea come together). The tissue that drains fluid from the angle is called the trabecular meshwork. This fluid nourishes your eye and helps to keep its shape. Glaucoma happens when the aqueous humor drains out of the eye too slowly, causing the pressure in the eye to increase. Higher pressure damages the optic nerve.

In some cases glaucoma develops even though the eye pressure is normal.

There are 2 main types of glaucoma, depending on how the flow of fluid is blocked:

• Open-angle glaucoma is caused by a gradual blockage in the trabecular meshwork. It is the more common type of glaucoma in the US and Europe. It usually affects both eyes. You have an increased risk of open-angle glaucoma if you are African American or if a family member has glaucoma.
• 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. Angle-closure glaucoma is more common among Asian people than white people, and it is rare in African Americans.

Glaucoma tends to run in families. It is a common eye problem in people over age 60.

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, starting with your side vision.

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

The eye care provider may:

• check for changes in your side vision caused by damage to the optic nerve
• look at the optic nerve inside your eye
• measure the pressure in your eyes and the thickness of your cornea
• examine the drainage channels with a special mirrored lens

How is it treated?

The goal of treatment is to reduce the pressure in your eyes and decrease damage to the optic nerve. This may be done with eyedrops, medicine taken by mouth, 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.

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 healthcare provider prescribes medicine 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 medicine as prescribed.
• Carefully follow your healthcare provider's instructions for follow-up exams.
• Call your healthcare provider if you have any side effects from your medicine.

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 regular eye exams. How often you need to see the eye care provider 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 healthcare provider right away 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 opth4216.htm Release 13/2010