The number of people who are in the process of losing their sight from conditions such as macular degeneration, diabetic retinopathy, glaucoma and cataracts is increasing in the United States, according to a new study in the Journal of the American Medical Association.
"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 researchers, from Johns Hopkins University School of Medicine, wrote in the study.
The study included 9,471 people ages 20 and older who were part of the National Health and Nutrition Examination Survey between 1999 and 2002, as well as 10,480 people ages 20 and older who were part of the survey between 2005 and 2008.
Researchers found a 21 percent increase in nonrefractive visual impairments -- meaning visual impairments not caused by the common problems of nearsightedness, farsightedness and astigmatism -- between the 1999-2002 period and the 2005-2008 period. Specifically, 1.4 percent of people had these kinds of visual impairments between 1999 and 2002, compared with 1.7 percent of people between 2005 and 2008.
Non-Hispanic white people between ages 20 and 39 had a 40 percent increase in nonrefractive visual impairments, with the prevalence going up from 0.5 percent in 1999-2002 to 0.7 percent in 2005-2008.
Researchers reported that factors such as poverty, diabetes and lower education level are all linked with these kinds of visual impairments, but that only diabetes has actually increased between the two time periods -- suggesting that it could play a role in the increased rates.
"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," the researchers wrote in the study.