Objective: To track and investigate the changes in visual acuity of primary and secondary school students in Henan Province during the COVID-19 pandemic home confinement, so as to provide theoretical basis for the prevention and control of myopia. Methods: A cohort study design was employed for this research. In September 2019, visual acuity tests were conducted among 2 222 primary and secondary school students by Multi stage random cluster sampling method from four cities in Henan Province, including Zhengzhou, Xinxiang, Zhoukou, and Pingdingshan. A follow up study was conducted in June 2020, with on site visual acuity tests and questionnaire surveys. Wilcoxon rank sum test, Kruskal Wallis rank sum test, Chi square test, one way analysis of variance, and multiple linear regression model were used to analyze the changes in visual acuity of primary and secondary school students and the influencing factors from 2019 to 2020. Results: Compared with 2019, the overall myopia rate of students increased in 2020, and the difference was statistically significant (55.7%, 64.9%, χ 2=1 035.91, P <0.01), and the difference between mild, moderate and severe myopia rates occurred at 2 years (2019:32.4%, 18.8%, 4.4%, 2020:36.7%, 22.5%, 5.7%, χ 2= 8.43, 9.23, 3.94, P <0.05). The myopia incidence rate of primary and secondary school students in 2020 was 28.3%. As presented in multiple linear regression analysis, middle school, grade 4th-6th and grade 1st-3rd of primary school, low economic level, using television for online classes, the study desk being not bright on sunny days, without looking far away during breaks, the brightness of the study desk and desktop which was average on sunny days, and using roof lamp only when studying at night were associated with myopia progression among students ( B=-0.16, -0.18, -0.20, -0.06, -0.21, -0.13, -0.11, -0.40, P <0.05). Conclusions During 2019-2020, primary and secondary school students in Henan Province experience a progression towards myopia, which is comprehensively influenced by education stage, economic level, the habit of using eyes, and visual environment. Myopia prevention and control should be actively intervened and strengthened to improve the eye environment for primary and secondary school students, in order to slow down the development of myopia.