Refractive changes in children in the Chicago area during the COVID-19 pandemic: a retrospective observational study.

Background: Remote learning during the COVID-19 pandemic caused behavioural changes such as increased screen time and decreased outdoor time. This study aimed to investigate myopia progression in children during the COVID-19 pandemic.

Methods: This was a retrospective observational study performed among 2064 patients ages 2-17 with cycloplegic refractions in the months of January 2019-March 2021 at a tertiary children's hospital. Exclusion criteria were a medical history of relevant connective tissue diseases, myopia control treatment, pseudophakia and aphakia.

Results: The overall cohort (n=2064) had a mean spherical equivalent (SE) of 0.12±3.70 D in 2019, -0.07±3.95 D in 2020 and -0.49±3.85 D in 2021. The change in mean SE (0.42 D) from 2020 to 2021 was 2.2 times greater than the change (0.19 D) from 2019 to 2020 at baseline. In the cohort of return patients, there was a significant difference in myopic shift between years (F-ratio=14.4, p<0.00001), and a significant change from 2020 to 2021 (p=0.00008) but not from 2019 to 2020. When observing the prevalence of myopia grouped by age, 8-year-old and 17-year-old patients had the greatest increase compared with baseline. When grouped by refractive error, low myopia children (-0.5 D to -3.00 D) displayed the greatest change in mean SE 2020-2021.

Conclusions: There was a substantial increase in myopia progression for children in the Chicagoland area after the period of COVID-19 changes. The behavioural changes of home confinement and online learning during the pandemic may explain these findings.