The number of Americans with vision loss not correctable by glasses is rising, caused in part by increasing diabetes rates, a study found.
The rate of non-refractive visual impairment jumped 21 percent in 2005-2008 from 1999-2002, according to research in the Journal of the American Medical Association.
About 2.15 million people ages 20 and older suffer from non-refractive visual impairment, which can take surgery or lasers to repair, said David Friedman, a study author. Based on the findings, more effort is needed to prevent diabetes and ensure that those who have the disease get yearly eye exams, he said.
"This is real, meaningful vision loss," Friedman, director of the Dana Center for Preventive Ophthalmology and a professor of public health ophthalmology at the Bloomberg School of Public Health at Johns Hopkins University in Baltimore, said. "We need to do everything we can to try to avoid diabetes altogether and make sure people diagnosed with diabetes are getting repeat eye care to treat anything that develops."
Diabetes, even if treated correctly, can cause cataracts to develop in the eyes. It can also lead to fluid in the retina causing vision loss or cause new blood vessels to grow in the eye damaging the retina, he said.
Eighteen states had at least a doubling of those living with diabetes since 1995, according to a report released Nov. 15 by the Centers for Disease Control and Prevention.
While those in the study with non-refractive visual impairment weren't legally blind, they suffered enough vision loss that they couldn't obtain an unrestricted driver's license in most states, he said.
Researchers in the study analyzed data from the National Health and Nutrition Examination Survey in 1999-2002 and 2005-2008, which included a representative sample of the U.S. population.
They found the rate of non-refractive visual impairment rose to 1.7 percent in 2005-2008 from 1.4 percent in 1999-2002. In total, Mexican Americans had the highest increase in the vision loss over the study, particularly those 60 and older.
The study also showed that people in their 20s and 30s were experiencing more vision loss. Non-Hispanic whites ages 20 to 39 had a 40 percent increase. For those in that age group who had had diabetes for 10 or more years, the rate more than doubled to 0.7 percent from 0.3 percent, the authors said.
The findings are "alarming" and reflect the repercussions of high obesity rates among children and adolescents, said David Musch, one of the authors of an accompanying editorial. Those who are obese have a higher risk of diabetes.
"If we can make an impact on obesity among children, we can prevent a lot of this," said Musch, a professor of ophthalmology and visual sciences at the University of Michigan Kellogg Eye Center in Ann Arbor.