Diabetic Eye Damage On the Rise?

Nearly 30% of diabetics in the U.S. over the age of 40 are thought to have diabetic retinopathy, with 4% of this population affected to the point of permanent vision loss, suggests a new study.

Retinopathy, caused by blood vessel damage behind the eye, has no obvious symptoms in the beginning. As damage progresses, however, floaters, blurred vision, night blindness, and other obvious signs become noticeable. Retinopathy is the leading cause of new cases of blindness among U.S. adults with diabetes between the ages of 20 and 74 years, costing the U.S. approximately $500 million annually. Lead researcher, Dr. Xinzhi Zhang, of the Centers for Disease Control and Prevention in Atlanta states, "The number of people with diabetes is increasing in this country. Estimates of how many Americans suffer from diabetic retinopathy remain more than a decade old."

To learn whether the condition is on the rise, or whether screening and treatment are keeping it under control, Dr. Zhang and his colleagues analyzed National Health and Nutrition Examination Survey (NHANES) data from 2005 to 2008. Out of 1,006 older adults with diabetes who had undergone diagnostic eye imaging, 29% had diabetic retinopathy and 4% had vision-threatening cases. The rates were about 40% percent and 250% higher, respectively, than estimates dating back to an earlier NHANES study from 1988 to 1994. "But we don't know if the increase is due to an actual rise in prevalence or if it is due to using a more precise method of assessing damage to eyes in the most recent study," noted Dr. Zhang, pointing out that the new study included two digital images of each eye compared to the previous study's single image of one eye.

The researchers also found that men had a significantly higher risk of developing diabetic retinopathy compared to women. Other risk factors included a longer duration with diabetes, use of insulin, high systolic blood pressure (the first number in a blood pressure reading), and high levels of hemoglobin A1c caused by uncontrolled glucose. Mexican Americans and non-Hispanic blacks also had significantly higher rates of the condition compared to non-Hispanic whites, the researchers reported online in the Journal of the American Medical Association.

Careful glucose management and yearly visits to the eye doctor are the best ways to prevent vision loss. "As the U.S. population ages and the proportion of racial minorities grows, it is important for the health care system to be prepared for the increasing demand", said Dr. Zhang. "With early detection and timely treatment, people have a good chance of preventing or reducing vision loss."

JAMA. August 11, 2010.

To learn more, go to http://www.cdc.gov/mmwr/preview/mmwrhtml/00019889.htm