(USA TODAY) -- The nation's rising level of diabetes is driving another health problem: a significant jump in adults with vision problems from a related condition called diabetic retinopathy.
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From 2000 to 2010, there was an 89 percent increase in the number of people with diabetic retinopathy, which affects the tiny blood vessels of the retina. The most severe forms can impair vision if not treated.
About 7.7 million people ages 40 and older have diabetic retinopathy, the new estimates say. The numbers emerge from an analysis, out Wednesday, by a group of researchers and sponsored by Prevent Blindness America and the National Eye Institute.
"The number we are most alarmed about is the increase in diabetic retinopathy, which is largely due to the diabetes epidemic," says Jeff Todd, chief operating officer of Prevent Blindness America.
Almost 26 million people in the USA have diabetes, the Centers for Disease Control and Prevention says. In diabetic retinopathy, high blood sugar causes small blood vessels to swell and leak into the retina, blurring vision and sometimes leading to blindness. A government study in 2008 found that about 4.2 million adults had the disease, the leading cause of blindness in adults.
"You can treat and stop progression," says Beatriz Muñoz, an associate professor of ophthalmology at the Wilmer Eye Institute at Johns Hopkins School of Medicine in Baltimore. But the disease can be "asymptomatic," or without symptoms: "You may not know you have it," she says. "So it's important to have regular eye exams."
The vision analysis found that overall, the number of people over 40 with vision impairment and blindness has increased 23 percent in the past decade, partly because of more people with eye conditions such as cataracts.
Vision impairment is defined as having worse than 20/40 vision in the better eye even with glasses. In the USA, people are typically considered blind with vision of 20/200 or worse in their best eye.
If the trend remains the same, about 13 million in the USA will have visual impairment or be blind by 2050, the report says.
"The increase we're seeing in eye diseases mirrors the increase in the aging population," Todd says.
Estimates for eye conditions:
- 24.4 million people 40 and older have cataracts, a 19 percent jump from 2000. A cataract is a clouding of the eye's clear lens that appears with age. Surgery is effective in restoring vision, Muñoz says, but "there is no clear way to prevent it."
- 2.7 million people ages 40 and older have open-angle glaucoma, the most common form of the disease, up 22 percent. Glaucoma causes damage to the optic nerve. Treatments can slow progression, she says.
- 2.1 million people ages 50 and older have late age-related macular degeneration, a 25 percent increase from 2000. Late AMD is the most severe form, and treatments can slow progression and prevent vision loss for some of the forms, Muñoz says.