Should All African Americans Get Glaucoma Screening?

March 16, 2012

By Andrew M. Seaman

NEW YORK (Reuters Health) Mar 15 - Screening middle-aged African Americans for glaucoma may prevent some from losing their vision, but the benefits are modest and costly, suggests a new study.

About 2% of Americans over age 40 are affected by glaucoma, it is a bigger threat to certain groups -- particularly African Americans.

Dr. Joseph Ladapo at New York University School of Medicine and colleagues wanted to know whether annual glaucoma screenings as part of a routine eye exam would stave off vision impairment or loss in some people.

"We thought (African Americans) would get hit the worst. So, if we can't show a benefit in this population, it's unlikely that we'll be able to show benefits in other populations," Dr. Ladapo told Reuters Health.

Dr. Ladapo and his colleagues created a computer simulation using data on African Americans between 50 and 59 years old in the Eye Diseases Prevalence Research Group and the Baltimore Eye Study.

Based on their calculations, the rate of undiagnosed glaucoma in African Americans would drop from 50% to 27% if regular screenings were adopted nationwide. However, the benefits of preventing vision loss or blindness were much more modest.

The proportion of African Americans blinded by glaucoma would go from 6.1% to 5.6%, and those with glaucoma-related vision impairment would fall from 4.6% to 4.4%.

While any reduction in glaucoma rates may prevent people from losing some or all of their vision, the researchers determined that 58 people would need to be screened to diagnose one case of glaucoma, and 875 people would have to be screened to prevent one person from losing some vision.

"It's just horrible when people develop visual impairment, but we didn't find that the benefits were that great," Dr. Ladapo told Reuters Health.

"My dad, who is a co-author on the paper, actually has glaucoma," Dr. Ladapo added. "He was diagnosed late and has some visual impairment from it... It's been a gradual process of different treatments and gradually worsening condition."

Preventing that one person from losing some vision would carry a price tag of over $70,000, the authors estimated.

But, the researchers write in the Archives of Ophthalmology, they consider the number needed to be screened to be comparable to other tests.

Dr. Nathan Radcliffe, director of Glaucoma Service at NY-Presbyterian/Weill Cornell Medical Center, said he also thinks it's important for people to be screened, because it's the only way to diagnose glaucoma and the examination may help find other unrelated conditions.

Dr. Radcliffe, who was not involved in the study, advises everyone over 40 and those with a family history of glaucoma-related vision loss to have a baseline exam.

He said glaucoma is treatable with drops or surgery, but "not once they've lost the main parts of their vision." Still, he added, "There is a huge window where we can diagnose glaucoma."


Arch Ophthalmol 2012.