AIM: To explore the current situation of myopia among children and adolescents in Mengzi city and the possible influencing factors of myopia.

METHODS: A multi-stage cluster sampling method was used to select students in 7 schools(2 primary schools, 2 junior high schools, 2 high schools, and 1 vocational high school)in Mengzi city, Yunnan Province in October 2019. A total of 1 837 students were selected for questionnaire surveys, and examination of distance visual acuity and noncycloplegic autorefraction. There were 1 622 valid questionnaires were finally collected after checking the integrity and rationality of the questionnaires.

RESULTS: The prevalence of myopia among primary and secondary students in Mengzi city in 2019 was 61.34%. The prevalence of myopia in girls(71.36%)was higher than that in boys(50.45%), and the prevalence of myopia in Han nationality(70.19%)was higher than that in ethnic minorities(57.70%). With the grade growth, the prevalence of myopia showed an upward trend. Multivariate Logistic regression analysis showed that the risk factors of myopia were female(OR=2.308), Han nationality(OR=1.712), higher learning stage(junior high school: OR=1.579, high school: OR=5.538), the time of doing homework daily in the past 1wk(1-<2h: OR=1.456, 2-<3h: OR=1.514, ≥3h: OR=1.901), occasionally or never keep your eyes more than one foot away from a book while reading and writing(OR=1.741), insufficient sleep(OR=1.585), parental myopia(OR=2.191).

CONCLUSION:The prevalence of myopia among primary and middle school students in Mengzi city is at a relatively high level. Female, Han nationality, higher learning stage, the time of doing homework daily in the past 1wk≥1h, occasionally or never keep your eyes more than one foot away from a book while reading and writing, insufficient sleep and parental myopia are all risk factors that can cause myopia.