It's not known why, but people with glaucoma typically experience an imbalance in eye fluid production and drainage. Fluid that normally flows in and out of the eye drains too slowly. As that fluid builds up, pressure in the eyeball increases and becomes abnormally high. This pressure can damage the optic nerve, the retina, or other parts of the eye.
Interestingly, there are also patients with glaucoma who actually have normal eye pressure, says Sheryl Berman, M.D., of the U.S. Food and Drug Administration (FDA). "This is why it is so critical to have dilated examinations, since routine pressure screening would miss the diagnosis of glaucoma in these eyes." For these people, there are other factors at play that may lead to optic nerve damage.
If glaucoma is left untreated, blindness is likely. The most common form of glaucoma is primary open-angle glaucoma, also known as chronic glaucoma. Nearly 3 million Americans have glaucoma, according to the National Eye Institute (NEI), and about half do not know it. That's because glaucoma is a silent stealer of sight; there are usually no symptoms in the early stages.
As the disease progresses, people with glaucoma might notice their side (peripheral) vision failing. But by this time, the disease is usually quite advanced and the damage is irreversible. Once vision is lost, it can't be restored. Glaucoma usually affects both eyes, one shortly after the other.
Ida Miggins, 52, a computer specialist from Takoma Park, Maryland, says she learned she had glaucoma three years ago by chance. She hadn't had an eye exam since childhood and hadn't noticed any vision problems. "I was actually taking my mother to her eye appointment, and the doctor suggested that I be checked too," says Miggins. The doctor diagnosed glaucoma in both eyes.
Risk Factors and Prevention
Early detection is the best way to control glaucoma and prevent major vision loss. Elevated pressure in the eye is the major risk factor for glaucoma. Other risk factors associated with the disease include having high blood pressure, diabetes, and certain diseases that affect blood vessels. Take steps to lower your blood pressure and control your diabetes.
A family history of the disease, aging, and African ancestry also increase your risk for glaucoma. Studies have shown that for unknown reasons, glaucoma presents at an earlier age in blacks, is five times more likely to occur in blacks than in whites, and is about four times more likely to cause blindness in blacks than whites.
Miggins, who is black, says she had heard of glaucoma. "But I didn't have a clue what it was, nor did I think I was at risk for it because it doesn't run in my family."
If you are in any of the high-risk groups for glaucoma--everyone over age 60, those with a family history of the disease, and blacks over age 40--you should get a complete eye exam at least every two years.
Treatment
Though glaucoma is not curable, there are treatments that successfully lower pressure in the eye. The first line of treatment is drugs. And whether you're prescribed eye drops or pills, taking your drugs as prescribed is critical.
The development of several classes of medications to reduce pressure in the eye has allowed for more effective treatment over time, says Wiley Chambers, M.D., of the FDA. For now, glaucoma medications only tackle eye pressure, says Chambers. "We're looking for treatments that can also protect the optic nerve."
Miggins says the first medication she took caused bleeding gums and eye pain. Some side effects may lessen over time, but be sure to report any side effect to your doctor because it could be that the drug or dose needs to be changed.
When glaucoma can't be controlled with medication, doctors might turn to laser surgery in which a focused beam of light creates openings in the part of the eye where fluid drains to make draining easier. The next line of treatment is a surgical procedure called trabeculectomy, in which a small opening is made in the front chamber of the eye to make a new pathway from which fluid can drain. Even with surgery, many patients who have glaucoma still need medication. |
