National Health and Nutrition Examination Survey (NHANES): Vision Procedures Manual

The vision examination is designed to test distance vision, measure refractive error, measure the shape of the cornea and, if applicable, measure the distance eyeglass prescription in SP’s aged 12 years and older. Near vision will be tested in SPs over 50 years of age. Vision loss is common in adults and prevalence increases with advancing age. Approximately 13 percent of individuals 65 years of age or older and 28 percent of those over 85 years of age report some degree of visual impairment. In children, refractive errors are the most common vision disorders, occurring in 20 percent by 16 years of age. More than 90 percent of older people require the use of corrective lenses at some time. Visual disorders in older adults frequently lead to trauma from falls, automobile crashes, and other types of unintentional injuries. Many adults are unaware of decreases in their visual acuity, and up to 25 percent may have incorrect corrective lens prescriptions.