Examining the impact of the pandemic on childhood myopia

The past 18 months has meant a lot more time in the home and on a screen for children. How has this affected the incidence of childhood myopia?

Over the past several months, many children have spent far more time indoors and staring at screens than would be typical in addition to significantly less time outside. This shift has led to worries that an increase in myopia would occur. A study from Hong Kong offers some much-needed data.1

Two separate longitudinal cohorts of children aged 6 to 8 years who lived in Hong Kong were included in the study. One cohort had been recruited before the COVID-19 pandemic and the other had been recruited at the start of the COVID-19 outbreak. Each child had a baseline as well as a series of follow-up visits, where he or she was given an ocular examination and completed a standardized questionnaire that asked about time spent outdoors and performing near work.

There were a total of 1793 children included in the study: 709 in the COVID-19 cohort, representing 7.89±2.30 months of follow-up, and 1084 in the pre-COVID-19 cohort, representing 37.54±3.12 months of follow-up. The overall incidence of myopia was 19.44% in the COVID-19 cohort and 36.57% in the pre-COVID-19 cohort. During the pandemic, the change in spherical equivalent refraction and axial length was –0.50±0.51 D and 0.29±0.35 mm, respectively. The time spent doing outdoor activities decreased from 1.27±1.12 to 0.41±0.90 hours/day (p<0.001), and screentime saw a significant increase from 2.45±2.32 to 6.89±4.42 hours/day (p<0.001).

The investigators concluded that there was a potential increase in myopia incidence as well as significant decreases in outdoor time and increases in screen time during the course of the COVID-19 pandemic. They believe that the findings should be a warning to parents, clinicians, and policymakers that increasing childhood myopia may be a looming public health crisis that may occur when we emerge from the current pandemic.


1. Zhang X, Cheung S, Chan HN, et al. Myopia incidence and lifestyle changes among school children during the COVID-19 pandemic: a population-based prospective study. British Journal of Ophthalmology. August 2, 2021. Epub ahead of print. doi:10.1136/bjophthalmol-2021-319307