More Americans losing vision to diabetes, study suggests

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An increasing number of Americans have lost their eyesight in recent years, and a new study shows diabetes may be to blame.

The new research finds that the number of U.S. adults who are losing their vision has climbed more than 20 percent over the past decade, rates that were even more pronounced in younger adults.

"If the current finding becomes a persisting trend, it could result in increasing rates of disability in the U.S. population, including greater numbers of patients with end-organ diabetic damage who would require ophthalmic care," wrote the researchers, led by Dr. Fang Ko, a resident at Johns Hopkins University School of Medicine.

Researchers reviewed data from the nationally representative National Health and Nutrition Examination Survey that were collected between 1999 and 2002 and 2005 and 2008. About 10,000 people ages 20 and older completed questionnaires during each time period, and were also given physical examinations, including an eye exam.

They were looking for rates of visual impairment that weren't caused by problems that could be corrected by glasses. Impairment was defined as visual acuity worse than 20/40. Visual acuity refers to the clarity or sharpness of vision, according to the American Optometric Association, and 20/20 vision is considered normal.

The researchers found from 1999 through 2002, about 1.4 percent of Americans had visual impairment, which rose to 1.7 percent between 2005 and 2008. That's a 21 percent rise in rates. A major 40 percent rise in vision problems was seen in non-Hispanic white Americans between 20 and 39 years old, which increased from 0.5 percent of that population to 0.7 percent during the studied time periods.

A closer look at the data showed risk for visual impairment increased with age and for those in poverty and with lower education levels. Another major risk they found was being diagnosed with diabetes 10 or more years prior to the survey. Diabetes prevalence rose from 2.8 percent in 1999-2002 to 3.6 percent in 2005-2008, a 22 percent rise in rates. During these time periods, diabetes rates rose for non-Hispanic whites between age 20 and 39 by a whopping 133 percent.

"These results have important implications for resource allocation in the debate of distribution of limited medical services and funding," write the researchers, who fear an influx of diabetic patients with eye problems.

The research was published Dec. 12 in JAMA, the Journal of the American Medical Association.

In an accompanying editorial published in the same journal, Drs. David C. Musch and Thomas W. Gardner, researchers at the University of Michigan in Ann Arbor, agree there is reason for concern given these corresponding increases in diabetes and eye problems.

"This report should send an important message to pediatricians, family practitioners, internists, and ophthalmologists who already are seeing an increase of Type 2 diabetes among their younger patients, and should alert public health planners, who need to prepare for the effects on the health care system," they write.

Diabetes can damage blood vessels in the eye, potentially causing impairment and blindness, according to the American Diabetes Association. Eye disorders related to diabetes include retinopathy; which is damage to the blood vessels in the back of the eye; glaucoma, which is vision loss caused by pressure build-up; and cataracts, which block out light from the eye.

Dr. Vivian Fonseca, president of medicine and science at the American Diabetes Association, said to HealthDay that on an individual level, people are better managing their diabetes and rates of diabetic retinopathy may actually be falling, according to some research.

"What's changed is the denominator," he said. "The overall prevalence of diabetes has gone up and the sheer volume of people with diabetes makes it look like things are getting worse."

Study co-author Dr. David Friedman, director of the Dana Center for Preventive Ophthalmology at the Johns Hopkins Wilmer Eye Institute in Baltimore, told Medscape the study backs current recommendations from the American Academy of Ophthalmology that urge people with diabetes to get routine eye exams.

"Virtually all permanent blindness from diabetes can be prevented with proper vision screening," said Friedman. "People with diabetes need an eye exam every year so we can prevent permanent vision loss from it."