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
National Center for Health Statistics (NCHS), Centers for Disease Control and Prevention; National Eye Institute, National Institutes of Health
The objective of this study is to describe the prevalence of refractive error in the United States.
The study used the 1999-2004 National Health and Nutrition Examination Survey (NHANES) data to estimate the population prevalence of refractive error and to describe the refractive characteristics of the US population in greater detail.
The 1999-2004 NHANES used an autorefractor to obtain refractive error data on a nationally representative sample of the US noninstitutionalized, civilian population 12 years and older. Using data from the eye with a greater absolute spherical equivalent (SphEq) value, clinically important refractive error was defined as as follows: hyperopia, SphEq value of 3.0 diopters (D) or greater; myopia, SphEq value of −1.0 D or less; and astigmatism, cylinder of 1.0 D or greater in either eye.
Of 14 213 participants 20 years or older who completed the NHANES, refractive error data were obtained for 12 010 (84.5%). The age-standardized prevalences of hyperopia, myopia, and astigmatism were 3.6% (95% confidence interval [CI], 3.2%-4.0%), 33.1% (95% CI, 31.5%-34.7%), and 36.2% (95% CI, 34.9%-37.5%), respectively.
Myopia was more prevalent in women (39.9%) than in men (32.6%) (P < .001) among 20- to 39-year-old participants. Persons 60 years or older were less likely to have myopia and more likely to have hyperopia and/or astigmatism than younger persons. Myopia was more common in non-Hispanic whites (35.2%) than in non-Hispanic blacks (28.6%) or Mexican Americans (25.1%) (P < .001 for both).
Estimates based on the 1999-2004 NHANES vision examination data indicate that clinically important refractive error affects half of the US population 20 years or older.
Refractive error is recognized as one of the most important causes of correctable visual impairment, accounting for nearly 80% of the visual impairment in persons 12 years and older in the United States.
Providing eye care services to the many persons who use or need refractive correction involves substantial expense: the direct annual cost of refractive correction for distance visual impairment is estimated to be between $3.8 and $7.2 billion for persons 12 years and older (based on an estimated annual direct cost per person of $35-$56) and, in a separate study of persons 40 years and older, $5.5 billion.
The study concluded that estimates based on the 1999–2004 NHANES vision examination data indicate that clinically important refractive error affects half of the U.S. population aged ≥20 years.