About half of U.S. adults age 20 and older have refractive errors, or eye problems that result in less than 20/20 vision, according to a report in the August issue of Archives of Ophthalmology, one of the JAMA/Archives journals.

Refractive error accounts for nearly 80 percent of vision impairment in U.S. residents 12 years and older, according to background information in the article. It occurs when the eye cannot properly focus light, resulting in nearsightedness, farsightedness or astigmatism, an irregular curve of the eye's cornea. Providing eye care to individuals age 12 and older who need glasses or contacts is estimated to cost between $3.8 and $7.2 billion per year.

Susan Vitale, Ph.D., M.H.S., and colleagues at the National Eye Institute, Bethesda, Md., analyzed data from the National Health and Nutrition Examination Survey (NHANES), an ongoing nationally representative survey conducted by the Centers for Disease Control and Prevention. Demographic characteristics were collected during in-person interviews and a vision examination was conducted.

Source: JAMA and Archives Journals