Increased Prevalence of Myopia in the United States Between 1971-1972 and 1999-2004

Objective: To compare US population prevalence estimates for myopia in 1971-1972 and 1999-2004. Methods: The 1971-1972 National Health and Nutrition Examination Survey provided the earliest nationally representative estimates for US myopia prevalence; myopia was diagnosed by an algorithm using either lensometry, pinhole visual acuity, and presenting visual acuity (for presenting visual acuity >= 20/40) or retinoscopy (for presenting visual acuity <= 20/50). Using a similar method for diagnosing myopia, we examined data from the 1999-2004 National Health and Nutrition Examination Survey to determine whether myopia prevalence had changed during the 30 years between the 2 surveys. Results: Using the 1971-1972 method, the estimated prevalence of myopia in persons aged 12 to 54 years was significantly higher in 1999-2004 than in 1971-1972 (41.6% vs 25.0%, respectively; P < .001). Prevalence estimates were higher in 1999-2004 than in 1971-1972 for black individuals (33.5% vs 13.0%, respectively; P < .001) and white individuals (43.0% vs 26.3%, respectively; P < .001.) and for all levels of myopia severity (>-2.0 diopters [D]: 17.5% vs 13.4%, respectively [P < .001]; <=-2.0 to >-7.9 D: 22.4% vs 11.4%, respectively [P < .001]; <=-7.9 D: 1.6% vs 0.2%, respectively [P<.001]). Conclusions: When using similar methods for each period, the prevalence of myopia in the United States appears to be substantially higher in 1999-2004 than 30 years earlier. Identifying modifiable risk factors for myopia could lead to the development of cost-effective interventional strategies.