Prevalence of refractive error within a Portuguese sample of optometric records Vera Lúcia Alves Carneiro; José Manuel González-Méijome;

The prevalence of refractive errors in college students in Israel Einat Shneor; Ravid Doron; Lisa A Ostrin; Ariela Gordon-Shaag;

Prevalence of astigmatism among 99,515 children in different areas of Xi'an City, China Ye Zhang; Xiaokang He; Wei Dong; Zihao Wang; Chengfei Liu; Yanying Li; Zhaojiang Du;