Changes in Refractive Error Under COVID-19: A 3-Year Follow-up Study

INTRODUCTION: To investigate changes in refractive error in schoolchildren before and during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: This study included 2792 students, who underwent a 3-year follow-up from 2018 to 2020. All participants underwent yearly noncycloplegic refraction and ocular examinations. Time-related changes in sphere, cylinder, and spherical equivalent (SE) measurements in both genders were analyzed. RESULTS: The myopic sphere (− 0.78 ± 1.83 vs. − 1.03 ± 1.91 D; P = 0.025) and SE (− 1.04 ± 1.90 vs. − 1.32 ± 1.99 D; P = 0.015) progressed significantly from 2018 to 2019. Female participants had a significantly greater change in SE than male participants (P < 0.05), and the low hyperopia, emmetropia, and mild myopia groups significantly deteriorated (P < 0.001) from 2018 to 2019. Significant differences in sphere change (− 0.21 ± 0.97 vs. − 0.36 ± 0.96 D; P < 0.001) and SE change (− 0.23 ± 0.99 vs. − 0.38 ± 0.98 D; P < 0.001) were noted between 2019–2018 and 2020–2019, respectively. The respective changes in cylinder were statistically similar (− 0.03 ± 0.53 vs. − 0.05 ± 0.62 D; P = 0.400). CONCLUSIONS: The refractive status of schoolchildren showed an increasing myopic shift trend before and during the COVID-19 pandemic. The low hyperopia, emmetropia, and mild myopia groups were more sensitive to environmental changes during COVID-19 than before. The myopic shift was greater in female participants than male participants.