News Release

USC Eye Institute study finds African-Americans at higher risk for diabetic vision loss

Study points to need for improved screening and access to treatments for diabetic macular edema, a leading cause of vision loss

Peer-Reviewed Publication

University of Southern California - Health Sciences

Rohit Varma, M.D., M.P.H., University of Southern California - Health Sciences

image: Rohit Varma, M.D., M.P.H., is the director of the USC Eye Institute and professor and chair of ophthalmology at the Keck School of Medicine of USC. view more 

Credit: Van Urfalian / © Keck Medicine of USC

LOS ANGELES — Research by Keck Medicine of USC ophthalmology scientists demonstrates that African Americans bear heavier burden of diabetic macular edema (DME), one of the leading causes of blindness in diabetic patients in the United States.

The research published online Aug. 14, 2014, in the Journal of the American Medical Association (JAMA) Ophthalmology, indicates a higher burden of diabetes-related vision loss among certain ethnic populations because of problems with access to care, said corresponding author Rohit Varma, M.D., M.P.H., director of the USC Eye Institute and professor and chair of ophthalmology at the Keck School of Medicine of USC.

"We were surprised that our research showed that African Americans have the highest rates of DME, when Hispanics tend to have the highest prevalence of diabetes," said Varma, who is recognized as one of the leading researchers of eye disease in underserved populations. "There is not enough vision screening for DME among diabetics, 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."

Diabetic eye disease is one of the leading causes of vision loss in people ages 20-70 years. Approximately 347 million people throughout the world have diabetes mellitus, and the Centers for Disease Control estimates that 25.8 million Americans had diabetes in 2010.

Diabetic macular edema results when fluid and protein accumulates on the macula of the eye, which is part of the retina, causing it to thicken and swell. The victim's central vision is affected and, left untreated, the condition can range from slight blurring to blindness.

Varma's team conducted the study by using the National Health and Nutrition Examination Study (NHANES) database, a national dataset measuring the health and nutritional status of American adults and children. The assessment has been surveying about 5,000 Americans every year since the early 1960s and is used by researchers nationwide to determine the prevalence of major diseases and risk factors for disease.

As part of NHANES, subjects undergo a physical exam that includes photos of their retinas, which Varma's team reviewed to determine the prevalence of DME.

Clinicians should assess diabetes patients, especially those who are African American or Hispanic, more closely for vision loss, Varma advised. He also stated that patients should do everything they can to control their glucose and monitor their own vision. Varma pointed out that August is when we commemorate National Eye Exam Month – a perfect time for ophthalmologists and patients to concentrate on eye health.

Varma's next target for research in this area is examining barriers to access to eye care among African Americans.


The study, "Prevalence of and risk factors for diabetic macular edema in the United States," was funded by Genentech, a pharmaceutical company. Varma is a consultant for Genentech.

The research team includes scientists from the Wilmer Eye Institute at Johns Hopkins University School of Medicine; Outcomes Insights, Inc.; The Ohio State University Division of Public Health; and Genentech, Inc.

The USC Eye Institute is one of the leaders in National Eye Institute funding and ranked No. 9 in the United States for ophthalmology care by U.S. News & World Report.


Varma, R.. Bressler, N.M.. Doan, Q.V.. Gleeson, M.. Danese, M.. Bower, J.K., … & Turpcu, A. (2014). Prevalence of and risk factors for diabetic macular edema in the United States. JAMA Ophthalmology. Published online Aug. 14, 2014; doi:10.1001/jamaophthalmol.2014.2854


The USC Eye Institute, part of Keck Medicine of USC, has consistently ranked as a Top 10 ophthalmology program by U.S. News & World Report and Ophthalmology Times and is No. 3 in research funding from the National Eye Institute. Led by Rohit Varma, M.D., M.P.H., the USC Eye Institute has 21 full-time faculty physicians covering all subspecialties of ophthalmology. The USC Eye Institute is headquartered near downtown Los Angeles and has satellite clinics in Pasadena, Beverly Hills and Arcadia. For more information, go to


Keck Medicine of USC is the University of Southern California's medical enterprise, one of only two university-based medical systems in the Los Angeles area. Encompassing academic, research and clinical excellence, the medical system attracts internationally renowned experts who teach and practice at the Keck School of Medicine of USC, the region's first medical school; includes the renowned USC Norris Comprehensive Cancer Center, one of the first comprehensive cancer centers established by the National Institutes of Health (NIH) in the United States; has a medical faculty practice, the USC Care Medical Group; operates the Keck Medical Center of USC, which includes two acute care hospitals: 401-licensed bed Keck Hospital of USC and 60-licensed bed USC Norris Cancer Hospital; and owns USC Verdugo Hills Hospital, a 158-licensed bed community hospital. It also includes more than 40 outpatient facilities, some at affiliated hospitals, in Los Angeles, Orange, Kern, Tulare and Ventura counties. For more information, go to

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