Refractive errors affect half of U.S. adults, survey says

A study has estimated that clinically relevant refractive errors affect half of the people in the United States aged 20 years or older.

Susan Vitale, PhD, MHS, and colleagues at the National Eye Institute determined the prevalence of refractive errors among a nationally representative sample of 14,213 participants in the 1999-2004 National Health and Nutrition Examination Survey. Of these participants, 12,010 who were 20 years or older underwent home interviews, as well as physical examinations and functional assessments.

For analysis, the investigators used data from the eye with a greater absolute spherical equivalent value. Hyperopia was defined as a spherical equivalent value of 3 D or greater, myopia as a spherical equivalent value of –1 D or less, and astigmatism as 1D or greater cylinder in either eye.

The investigators reported a 3.6% age-standardized prevalence of hyperopia, a 33.1% prevalence of myopia and a 36.2% prevalence of astigmatism.

Among participants between the ages of 20 and 39 years, myopia was more prevalent in women (39.9%) than in men (32.6%; P < .001). Hyperopia and astigmatism were more likely to occur in participants aged 60 years or older than in younger participants, who were more likely to have myopia.

While the investigators found no difference in hyperopia and astigmatism prevalence among race and ethnicity categories, the prevalence of myopia was higher in non-Hispanic whites (35.2%) than in non-Hispanic blacks (28.6%) or Mexican Americans (25.1%; P < .001 for all); however, they found no race or ethnicity difference in participants aged 60 years or older, according to the study, published in the August issue of Archives of Ophthalmology.