Researchers analyzed data from the U.S. National Health and Nutrition Examination Survey, which evaluates about 5,000 people each year. They found that blacks had the highest rates of a condition known as diabetic macular edema -- one of the leading causes of blindness in people with diabetes.
Diabetic macular edema occurs when fluid and protein builds up in a part of the retina. This causes retinal swelling and a resulting loss of vision, the researchers explained.
"We were surprised that our research showed that African Americans have the highest rates of diabetic macular edema, when Hispanics tend to have the highest prevalence of diabetes," study corresponding author Dr. Rohit Varma, director of the University of Southern California's Eye Institute and professor and chair of ophthalmology at the Keck School of Medicine, said in a university news release.
The findings highlight the need for improved screening and access to treatments for diabetic macular edema, the researchers said.
Varma believes there's a lack of vision screening among people with diabetes, "yet there are much better therapies available that are covered by insurance. We hope that our research will help those in the position to influence policy to get a better handle on costs and where the need for treatment is the greatest."
The study, published online Aug. 20 in the journal JAMA Ophthalmology, was funded by drug maker Genentech. Varma is a consultant for the company.
Doctors should assess diabetes patients, especially blacks and Hispanics, more closely for vision loss, and patients need to do all they can to control their blood sugar levels and monitor their vision, Varma said.
Diabetes-related eye disease is one of the leading causes of vision loss in people ages 20 to 70. Nearly 26 million Americans had diabetes in 2010, according to the U.S. Centers for Disease Control and Prevention.
The U.S. National Library of Medicine has more about diabetic eye problems.