Rates of Myopia Development in Young Chinese Schoolchildren During the Outbreak of COVID-19

IMPORTANCE During the outbreak of COVID-19, outdoor activities were limited and digital learning increased. Concerns have arisen regarding the impact of these environmental changes on the development ofmyopia. OBJECTIVE To investigate changes in the development ofmyopia in young Chinese schoolchildren during the outbreak of COVID-19. DESIGN, SETTING, AND PARTICIPANTS In this observational study, 2 groups of students from 12 primary schools in Guangzhou, China, were prospectively enrolled and monitored from grade 2 to grade 3. Comparisons between the exposure and nonexposure groups were made to evaluate any association between environmental changes during the COVID-19 outbreak period and development ofmyopia. The exposure group received complete eye examinations in November and December 2019 and November and December 2020. The nonexposure group received examinations in November and December 2018 and November and December 2019. MAIN OUTCOMES AND MEASURES Changes in cycloplegic spherical equivalent refraction (SER), axial length (AL) elongation, andmyopia incidence from grade 2 to grade 3. RESULTS Among the 2679 eligible students in grade 2 (mean [SD] age, 7.76 [0.32] years; 1422 [53.1%] male), 2114 (1060 in the nonexposure group and 1054 in the exposure group) were reexamined in grade 3. Compared with the period from November and December 2018 to November and December 2019, the shift of SER, AL elongation, andmyopia incidence from grade 2 to grade 3 from November and December 2019 to November and December 2020 was 0.36 D greater (95% CI, 0.32-0.41; P <.001), 0.08mmfaster (95% CI, 0.06-0.10; P <.001), and 7.9% higher (95% CI, 5.1%-10.6%; P <.001), respectively. In grade 3 students, the prevalence ofmyopia increased from 13.3%(141 of 1060 students) in November and December 2019 to 20.8%(219 of 1054 students) in November and December 2020 (difference [95% CI], 7.5%[4.3-10.7]; P <.001); the proportion of children withoutmyopia and with SER greater than -0.50 D and less than or equal to +0.50 D increased from 31.1%(286 of 919 students) to 49.0%(409 of 835 students) (difference [95% CI], 17.9%[13.3-22.4]; P <.001). CONCLUSIONS AND RELEVANCE In this study, development ofmyopia increased during the COVID-19 outbreak period in young schoolchildren in China. Consequently, myopia prevalence and the proportion of children withoutmyopia who were at risk of developing myopia increased. Future studies are needed to investigate long-term changes inmyopia development after the COVID-19 pandemic.