Analysis of the National Health and Nutrition Examination Survey. Comment on "Prevalence of visual impairment in the United States", by S Vitale, MF Cotch, and RD Sperduto. JAMA 295:2158-63, 2006.
BACKGROUND
The prevalence of visual impairment in the U.S. public has not been surveyed nationally in several decades.


OBJECTIVE
To estimate the number of U.S. individuals aged 12 years or older who have impaired distance vision due to uncorrected refractive error.


METHODS
The National Health and Nutrition Examination Survey (NHANES), using a multistage probability sampling design, included a vision evaluation in a mobile examination center. Visual acuity data were obtained from 13,265 of 14,203 participants (93.4%) who visited the mobile examination center in 1999-2002. Visual impairment was defined as presenting distance visual acuity of 20/50 or worse in the better-seeing eye. Visual impairment due to uncorrected refractive error was defined as (presenting) visual impairment that improved, aided by automated refraction results, to 20/40 or better in the better-seeing eye.


METHODS
Presenting distance visual acuity (measured with usual corrective lenses, if any) and distance visual acuity after automated refraction.


RESULTS
Overall, 1,190 study participants had visual impairment (weighted prevalence, 6.4%; 95% confidence interval [CI], 6.0-6.8%), and of these, 83.3% could achieve good visual acuity with correction (95% CI, 80.9-85.8%). Extrapolating these findings to the general U.S. population, approximately 14 million individuals aged 12 years or older have visual impairment (defined as distance visual acuity of 20/50 or worse), and of these, more than 11 million individuals could have their vision improved to 20/40 or better with refractive correction.


CONCLUSIONS
Visual impairment due to uncorrected refractive error is a common condition in the United States. Providing appropriate refractive correction to those individuals whose vision can be improved is an important public health endeavor with implications for safety and quality of life.
Carden
Susan M
SM
D006801:Humans; D009749:Nutrition Surveys; D015995:Prevalence; D012030:Refractive Errors / Q000453:epidemiology*; D014481:United States / Q000453:epidemiology; D014786:Vision Disorders / Q000453:epidemiology*; D014792:Visual Acuity; D019987:Persons with Visual Disabilities / Q000706:statistics & numerical data*