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An Eye to Blindness

As type 2 diabetes hits growing numbers of the nation’s burgeoning Latino population, diabetic retinopathy is stealing the eyesight of almost one in 10 adult Latinos, according to results of a new USC study.

The findings were presented recently at the annual meeting of the Association for Research in Vision and Ophthalmology.

Rohit Varma, associate professor of ophthalmology at the Keck School of Medicine of USC and the Doheny Eye Institute, led the Los Angeles Latino Eye Study, a five-year effort to track the causes of vision problems, blindness and access to eye care among the nation’s fastest-growing ethnic group.

The study was conducted primarily among Los Angeles-area residents of Mexican descent.

The Latino Eye Study team enrolled more than 6,200 Latino men and women over age 40 who lived in communities in and around the city of La Puente, Calif.

Researchers screened participants for eye disease, high blood pressure and diabetes. They also interviewed participants to gather information about eye disease risk factors, such as weight, health-care access, family history of eye disease and tobacco and alcohol use.

Overall, the study found high rates of diabetic retinopathy, early macular degeneration and glaucoma, Varma said.

Diabetes can cause tiny blood vessels in the retina to clog or leak – the condition known as diabetic retinopathy.

“Diabetic retinopathy makes sense because Latinos’ rates of diabetes are so high,” Varma said.

Of the initial 5,238 study participants checked for diabetes, 1,237 (nearly 24 percent) had the disease. More than a quarter of those with diabetes were previously undiagnosed.

About 46 percent of the Latinos with diabetes had diabetic retinopathy, Varma said.

National data show that 29 percent of black adults with type 2 diabetes and 37 percent of whites with type 2 diabetes have diabetic retinopathy.

Over time, diabetic retinopathy may seriously impair vision and even cause blindness.

The study also found that about two thirds of participants who reported having diabetes were not following the American Diabetes Association’s guidelines for vision care, which recommend having annual dilated eye exams.

“Few Latinos actually follow the guidelines, and that’s worrisome,” Varma said.

Varma and colleagues also found early macular degeneration among Latinos at a rate higher than that of whites.

However, rates of late macular degeneration are about the same between both groups, said the researcher.

“We’re not sure why. It could be that the Latinos tend to die before they develop late macular degeneration, or something could stall progression of their disease,” he said.

Finally, the researchers found glaucoma in 84 of 2,677 participants evaluated for the disease, or 3 percent. Three quarters of those found with glaucoma had never been diagnosed.

“Rates of glaucoma in Latinos are higher than those in whites and similar to those in blacks, who have high rates,” Varma said.

Varma said the study points out the need to reach out to Latinos with better information about vision screenings and address issues of vision insurance.

The USC researcher hopes that health educators will use the data to find effective outreach strategies and that health-care workers in local communities will use the study’s findings to plan services.

The data also will be useful to national health policymakers trying to understand the breadth of public health problems, as well as to scientists seeking the reasons behind ethnic differences in disease prevalence.

Keck School faculty members Stanley P. Azen, Susan Preston-Martin and Ronald Smith were investigators in the study. The National Eye Institute supported the research.

Contact Jon Weiner at (323) 442-2823.

An Eye to Blindness

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