Prevalence of Myopia in America

In recent years, prevalence of myopia in the world has increased significantly. The aim of this research work is to consider the combined prevalence of myopia in America, according to the following categories: age, race, gender, and region. Such research will be done also in harmony with the reports found in scientific literature. A systematic review of the literature found in the following databases was carried out: medline, embase, and lilacs. The aim was searching cross-sectional studies containing myopia prevalence information. To find the combined prevalence, the double arc sine method of fixed or random effects by Freeman-Tukey was used. 15 research studies that included 45.349 individuals from the United States, Brazil, and Paraguay, were identified in the literature; studies of subjects aged 0-96 years old. The prevalence of myopia varied from 1,2% to 48% with differences between male and female of 18,4% [95% CI: 13,9-22,8] and 19,8% [95% CI: 18,9-20,7], respectively. The global prevalence of myopia in rural areas was 1,4% [95% CI: 1,3-1,5], and in urban areas 14,3% [95% CI: 13,3-15,2]. At the same time, some differences were identified based on race. In the case of the white race 15,4% [95% CI: 14,4-16,3], Afrodescendants 20,6% [95% CI: 19,6-21,5] and other races (Spanish, non-Spanish, and African American) 2,9% [95% CI: 1,97-3,82]. The lowest figures of myopia prevalence were identified in rural areas in pre-school children (14,1%). There is, probably, a relationship in use and exposure time to electronic items such as screens, in contrast with the development of other indoor activities as outdoor exposure as an environmental factor to slow myopia.