... representative of the whole China, especially the de-veloping regions. Western China is very vast (6.8 million square kilometers, accounting for 71% of the area in main-land China), and includes ... results of epidemiological studies from China [8, 9, 10] and the prevalence of myopia is higher in China, indicating that differences in ethnicity, regional and economical differences and ... included. During door-to-door selection interviews, a parent or legal guardian of the child was informed of the study details, including the side effects of pupil-lary dilation and cycloplegia and the...