Approximately half of all adults in the United States aged 20 and older have refraction errors in their eyes that result in less than 20/20 vision, according to an article released on August 11, 2008 in the Archives of Ophthalmology, one of the JAMA/Archives journals.
When the eye does not properly focus light on the retina, it results in nearsightedness, farsightedness, or astigmatism. These refractive errors account for nearly 80% of vision impairment in residents older than 12 in the United States. Providing eye care to this population, including glasses and contact lenses, costs and estimated $3.8 to $7.2 billion US dollars per year.
To investigate the prevalence of refractive error in the U.S. public, Susan Vitale, Ph.D., M.H.S., and colleagues at the National Eye Institute, part of the National Institutes of Health in Bethesda, analyzed data taken as part of the National Health and Nutrition Examination Survey (NHANES) conducted by the Centers for Disease Control and Prevention (CDC). In this survey, a nationally representative sample was selected and noted for demographic characteristics, and a vision test was administered.
A total 12,010 participants over age 20 performed the survey between 1999 and 2004 with complete data. Approximately half of these adults had one type of refractive error, including 3.6% who were farsighted, 33.1% who were nearsighted, and 36.2% who had astigmatism. Refractive error of any kind increased with age, from the youngest age group from 20-39 years (46.3%) to those 40 through 59 (50.6%) to the oldest group aged 60 or older (62.7%).
Comparing age and sex yielded additional results. Nearsightedness was less common in those older than 60, but this age group was more likely to have farsightedness and astigmatism than others. Additionally, in this older age group, men were more likely to have refractive error than women (66.8% versus 59.2%). Among 20 to 39 year olds, women were more likely to be nearsighted than men (39.9% versus 32.6%).
When analyzing ethnicity, Mexican-Americans were less likely to have refractive errors than non-Hispanic whites or non-Hispanic blacks.
The authors conclude that refractive error is a highly prevalent condition among the American public. “Refractive error is, therefore, the most common condition affecting the ocular health of the U.S. population, involving young adults, middle-aged persons and older adults of all ethnicities,” they say. “Accurate, current estimates of the prevalence of refractive error are essential for projecting vision care needs and planning for provision of vision care services to the many people affected.”
Prevalence of Refractive Error in the United States, 1999-2004
Susan Vitale, PhD, MHS; Leon Ellwein, PhD; Mary Frances Cotch, PhD; Frederick L. Ferris III, MD; Robert Sperduto, MD
Arch Ophthalmol. 2008;126(8):1111-1119.
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Written by Anna Sophia McKenney