FRIDAY, March 16 (HealthDay News) -- Middle-aged black people may benefit from a routine national glaucoma screening program, according to new research.

A computer-based mathematical model found routine screening could make a modest reduction in the number of people who go blind or become visually impaired from the eye disease.

Glaucoma is a chronic, degenerative disease that affects more than 2.2 million Americans and nearly 2 percent of Americans older than age 40, according to the study authors. There are several types, the most common of which is open-angle chronic glaucoma, which occurs when pressure builds in the eye and puts pressure on the optic nerve.

Yet, many cases go undiagnosed. "The high prevalence of undiagnosed glaucoma contributes to visual loss, an outcome that is disproportionately common in African American individuals," the authors wrote.

Using data from the Eye Diseases Prevalence Research Group and Baltimore Eye Study, researchers from Beth Israel Deaconess Medical Center and Harvard Medical School simulated what the effects would be of a national glaucoma screening policy for black people.

The researchers found that a universal, community-based glaucoma screening program for black people aged 50 to 59 without glaucoma would reduce the prevalence of undiagnosed glaucoma over their lifetime from 50 percent to 27 percent. The analysis also found the program would reduce glaucoma-related visual impairment from 4.6 percent to 4.4 percent, and glaucoma-related blindness from 6.1 percent to 5.6 percent.

The study was published in the March issue of the Archives of Ophthalmology.

For every 58 people screened, one person would be diagnosed with glaucoma, according to the study, while 875 people would need to be screened to prevent one person from becoming visually impaired.

Researchers estimated costs at about $80 for each person screened and examined to confirm a diagnosis. They did not, however, factor in the cost of visual rehabilitation, disability or long-term care in patients with blindness.

"We conclude that routine screening for glaucoma in African American individuals is a potentially clinically effective and economical method to reduce the burden of glaucoma-related visual impairment and blindness, though its absolute benefit is likely to be modest," the authors wrote. "Future studies should also consider long-term costs associated with treatment and the impact of delaying visual impairment on health-related quality of life."

More information

The U.S. National Institutes of Health provides more information on glaucoma.