Early treatment with eye drop medication can help African-American patients with elevated eye pressure, also known as ocular hypertension, to prevent the development of the most common form of glaucoma, primary open-angle glaucoma. That's according to University of Maryland eye specialists who were part of a national, multi-year study published in the June 2004 issue of Archives of Ophthalmology.
The Ocular Hypertension Treatment Study also found that not every African-American patient with ocular hypertension may require treatment; instead, researchers say physicians should focus on biological risk factors, such as thickness of the cornea, rather than relying on an individual's ethnicity as an indication for treatment.
"The study shows the importance of getting high-risk patients to seek treatment earlier," says Eve J. Higginbotham, M.D., professor and chair of ophthalmology at the University of Maryland School of Medicine and chief of ophthalmology at the University of Maryland Medical Center. She adds, "Glaucoma is the leading cause of blindness in African-Americans. This study found that daily pressure-lowering drops reduced the development of primary open-angle glaucoma in African-Americans by almost 50 percent." Dr. Higginbotham is the lead author of the journal article and one of three vice chairs for the national study.
For this study, researchers at 22 centers across the country followed more than 1,600 people, including 408 African-Americans, ages 40-80, who had elevated eye pressure but no signs of glaucoma. Elevated eye pressure occurs when the fluid that flows in and out of the eye drains too slowly, gradually increasing pressure inside the eye. Elevated eye pressure increases the risk of developing primary open-angle glaucoma.
Researchers followed study participants for more than six years. Of the African- American study participants who received eye drops, 8.4 percent developed glaucoma compared to 16.1 percent of the African-American patients who did not receive the eye drops.
"The study results underscore that African-Americans over age 40 should receive a comprehensive dilated eye exam at least once every two years to see if they are at higher risk for glaucoma. If so, this treatment may help save their sight,"says Paul A. Sieving, M.D., Ph.D., director of the National Eye Institute (NEI). The NEI and the National Center on Minority Health and Health Disparities funded the study. Both agencies are part of the National Institutes of Health.
Primary open-angle glaucoma affects more than two million Americans age 40 and over; half of these people may not be aware that they have the disease. Glaucoma occurs when the optic nerve is damaged. In most cases, elevated eye pressure contributes to this damage, causing a gradual loss of peripheral vision. By the time people notice vision problems, they usually have a significant amount of optic nerve damage.
African-Americans are more than three times as likely as Caucasians to develop glaucoma. According to Michael Kass, M.D., of the University of Washington Department of Ophthalmology and chair of the study, "A number of risk factors may be contributing to the increased prevalence of visual impairment from glaucoma in African- Americans. These include a family history of glaucoma, earlier onset of the disease, later detection, and economic and social barriers to treatment."
However, the study results do not imply that every African-American with ocular hypertension requires treatment. "Doctors need to take into account several risk factors, including specific characteristics in the anatomy of the optic nerve and the thickness of the cornea," explains Dr. Higginbotham.
Before determining treatment, the physician and patient should discuss the patient's health history as well as the impact of daily treatment, including cost, inconvenience and possible side effects.
This study focusing on African-Americans is a follow-up to initial results released two years ago. In those findings, researchers discovered that treating people with elevated eye pressure could delay or prevent the onset of glaucoma. Results for African-Americans in the earlier study trended in the same direction but were not conclusive, possibly because of a shorter follow-up time. These new results make a clear connection between elevated eye pressure in African-Americans and the benefits of early treatment.
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