Glaucoma is not just one eye disease, but a group of eye conditions resulting in optic nerve damage, which may cause loss of vision. Abnormally high pressure inside your eye (intraocular pressure) usually, but not always, causes this damage.
Glaucoma is one of the leading causes of blindness in the United States. Glaucoma can damage your vision so gradually you may not notice any loss of vision until the disease is at an advanced stage. The most common type of glaucoma, primary open-angle glaucoma, has no noticeable signs or symptoms except gradual vision loss.
Early diagnosis and treatment can minimize or prevent optic nerve damage and limit glaucoma-related vision loss. It's important to get your eyes examined regularly. Glaucoma is a condition you should have checked during your regular comprehensive ophalmologic exam.
Because chronic forms of glaucoma can destroy vision before any signs or symptoms are apparent, be aware of these factors:
- Elevated internal eye pressure (intraocular pressure). If your internal eye pressure (intraocular pressure) is higher than normal, you're at increased risk of developing glaucoma, though not everyone with elevated intraocular pressure develops the disease.
- Age. You're at a higher risk of glaucoma if you're older than age 60, particularly if you're Mexican-American. You may be at higher risk of angle-closure glaucoma if you're older than age 40. For certain groups such as African-Americans, however, the risk of developing glaucoma is much higher and occurs at a younger age than that of other groups. If you're African-American, ask your doctor when you should start having regular comprehensive eye exams.
- Ethnic background. African-Americans older than age 40 have much higher risk of developing glaucoma than do whites (Caucasians). African-Americans also are more likely to experience permanent blindness as a result of glaucoma. People of Asian descent have an increased risk of developing acute angle-closure glaucoma. People of Japanese descent may be more likely to have normal-tension glaucoma.
- Family history of glaucoma. If you have a family history of glaucoma, you have a greater risk of developing it. Glaucoma may have a genetic link, meaning there's a defect in one or more genes that may cause certain individuals to be more susceptible to the disease. A form of juvenile open-angle glaucoma has been clearly linked to genetic abnormalities.
- Medical conditions. Several conditions may increase your risk of developing glaucoma, including diabetes, heart diseases, high blood pressure and hypothyroidism.
- Other eye conditions. Severe eye injuries can cause increased eye pressure. Other eye conditions that could cause increased risk of glaucoma include eye tumors, retinal detachment, eye inflammation and lens dislocation. Certain types of eye surgery also may trigger glaucoma. Also, being nearsighted or farsighted may increase your risk of developing glaucoma.
- Long-term corticosteroid use. Using corticosteroid medications, especially eyedrops for a long period of time may increase your risk of developing secondary glaucoma.
Dr. Mary may perform several tests to diagnose glaucoma, including:
- Measuring intraocular pressure. Tonometry is a simple, painless procedure that measures your internal eye pressure (intraocular pressure), after numbing your eyes with drops. It's usually the initial screening test for glaucoma.
- Visual Test for optic nerve damage. To check for damage in your optic nerve, your eye doctor uses instruments to look directly through the pupil to the back of your eye. This can reveal slight changes that may indicate the beginnings of glaucoma.
- Visual field test. To check whether your visual field has been affected by glaucoma, your doctor uses a special test to evaluate your side (peripheral) vision.
- Visual acuity. Your doctor will test your ability to see from a distance.
- Measuring cornea thickness (pachymetry). Your eyes are numbed for this test, which determines the thickness of each cornea, an important factor in diagnosing glaucoma. If you have thick corneas, your eye-pressure reading may read higher than normal even though you may not have glaucoma. Similarly, people with thin corneas can have normal pressure readings and still have glaucoma.
- OCT (Optical Coherance Tomography) is a procedure that uses a computer to evaluate the retina in both macular degeneration and glaucoma.
- Other tests. To distinguish between open-angle glaucoma and angle-closure glaucoma, your eye doctor may use a technique called gonioscopy in which a special lens is placed on your eye to inspect the drainage angle. Other tests, such as imaging tests, have been developed and may sometimes be used.
The goal of glaucoma treatment is to lower pressure in your eye (intraocular pressure). To treat your condition, doctors may lower your eye pressure, improve drainage of fluid in your eye or lower the amount of fluid produced in your eye.
Glaucoma can't be cured, and damage caused by the disease can't be reversed, but treatment and regular checkups can prevent vision loss in people with early glaucoma. If vision loss has already occurred, treatment can slow or prevent further vision loss.
Laser surgery. You may have an outpatient procedure called laser trabeculoplasty (truh-BEK-u-low-plas-tee) to treat open-angle glaucoma. After giving you a numbing eyedrop, your doctor uses a high-energy laser beam to open clogged drainage canals and help fluid drain more easily from your eye.
Your doctor will need to check your eye pressure several times in the following weeks. It may take a few weeks before the full effect of the surgery becomes appareent.
Glaucoma treatment often starts with medicated eyedrops. Be sure to use the drops exactly as prescribed. Otherwise, your optic nerve damage could get even worse. If your doctor prescribes more than one type of eyedrop, make sure to ask how long to wait between applications and to take the drops for as long as your doctor has prescribed them.
Filtering surgery. If eyedrops and laser surgery aren't effective in controlling your eye pressure, you may need a surgical procedure called a trabeculectomy (truh-bek-u-LEK-tuh-me).
This procedure is performed in a hospital or an outpatient surgery center. You'll receive a medication to help you relax and usually an injection of anesthetic to numb your eye. Using small instruments under an operating microscope, your surgeon creates an opening in the sclera — the white of your eye — and removes a small piece of eye tissue at the base of your cornea through which fluid drains from your eye (the trabecular meshwork). The fluid in your eye can now freely leave the eye through this opening. As a result, your eye pressure will be lowered.
Your surgery will be performed on one eye. If necessary, several weeks later you might have surgery on the other eye. You may need additional procedures or treatments, as the opening sometimes heals over or other changes occur in your optic nerve.
Your doctor will check your eye during several follow-up visits, and you'll need to use antibiotic and anti-inflammatory eyedrops to fight infection and scarring of the newly created drainage opening.
Another procedure performed within the eye removes a targeted strip of the trabecular meshwork with a small tool. Your surgeon inserts the tool into the eye's drainage canal through a small incision at the edge of the cornea and removes the small section of trabecular meshwork. This helps fluid drain more easily from your eye.