Vision loss and blindness can be devastating, isolating people and increasing their risk of illness and death. And that burden falls hardest on people in poor communities, especially in the South.

More than three quarters of the counties with the highest rates of severe vision loss are in the South, according to an analysis published Thursday in Morbidity and Mortality Weekly Report. It's the first analysis of severe vision loss at the county level.

Nationwide, 2.6 percent of adults said they had severe vision loss, but the prevalence by county varied from less than 1 percent to 18 percent.

More than half of the counties with high rates of severe vision loss also had high rates of poverty.

Cataracts, diabetic retinopathy, glaucoma and macular degeneration are the most common causes of vision loss in adults. Some, like cataracts, are easily treated once they're diagnosed. Others, like macular degeneration, can be managed but not cured.

Regular eye exams would identify problems early on, before people start losing vision, the report notes. And in many cases, people can't see well just because they don't have the right glasses. But vision care isn't covered in many insurance plans. Medicare provides eye exams only for people with diabetes or at high risk of glaucoma.

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