The incident of visual impairment is increasing in the United States and diabetes is one of the major factors, according to a new study in the December 12 issue of JAMA.
The researchers found that prevalence of nonrefractive visual impairment--meaning something other than simple nearsightedness or farsightedness--increased 21 percent, from 1.4 percent in 1999-2002 to 1.7 percent in 2005-2008. It increased 40 percent among non-Hispanic whites 20-39 years of age, from 0.5 percent to 0.7 percent.
“We report a previously unrecognized increase of visual impairment among U.S. adults," the authors write. “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."
The study identifies yet another risk associated with the rising tide of obesity among younger Americans, said an editorial that accompanied the study.
“[T]his 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," said David C. Musch, Ph.D., M.P.H., and Thomas W. Gardner, M.D., M.S., of the University of Michigan, Ann Arbor. "The findings ... should also stimulate funding for new and ongoing efforts to prevent the underlying causes that lead to diabetes and its complications such as obesity-prevention programs aimed at children and adolescents."
It is estimated that more than 14 million individuals in the United States aged 12 years and older are visually impaired, meaning their uncorrected vision is less than 20/40. Of those 14 million, 11 million are due to simple refractive error that can be corrected with eyeglasses.
"In the United States, the most common causes of nonrefractive visual impairment are age-related macular degeneration, cataract, diabetic retinopathy, glaucoma, and other retinal disorders,” according to background information in the article. Previous studies have shown that visual impairment is common in persons with diabetes.
The study notes that the prevalence of diagnosed diabetes has increased among adults in recent years, rising from 4.9 percent in 1990 to 6.5 percent in 1998, 7.9 percent in 2001, 10.7 percent in 2007, and 11.3 percent in 2010.
Fang Ko, M.D., of the Johns Hopkins University School of Medicine, Baltimore, and colleagues conducted a study to assess the prevalence of nonrefractive visual impairment and factors associated with risk of visual impairment.They found that prevalence of nonrefractive visual impairment increased 21 percent, from 1.4 percent in 1999-2002 to 1.7 percent in 2005-2008; and increased 40 percent among non-Hispanic whites 20-39 years of age, from 0.5 percent to 0.7 percent.
In analysis among all participants, factors associated with nonrefractive visual impairment included older age, poverty, lower education level, and diabetes diagnosed 10 or more years ago. Among these risk factors, only the latter has increased in prevalence between the two time periods considered.
Prevalence of diabetes with 10 or more years since diagnosis increased 22 percent overall from 2.8 percent to 3.6 percent; and 133 percent among non-Hispanic whites 20-39 years of age, from 0.3 percent to 0.7 percent.