Progression of Myopia in School-Aged Children After COVID-19 Home Confinement

Abstract

Importance: Time spent in outdoor activities has decreased owing to home confinement for the coronavirus disease 2019 (COVID-19) pandemic. Concerns have been raised about whether home confinement may have worsened the burden of myopia owing to substantially decreased time spent outdoors and increased screen time at home.

Objective: To investigate the refractive changes and prevalence of myopia in school-aged children during the COVID-19 home confinement.

Design, setting, and participants: A prospective cross-sectional study using school-based photoscreenings in 123 535 children aged 6 to 13 years from 10 elementary schools in Feicheng, China, was conducted. The study was performed during 6 consecutive years (2015-2020). Data were analyzed in July 2020.

Exposures: Noncycloplegic photorefraction was examined using a photoscreener device.

Main outcomes and measures: The spherical equivalent refraction was recorded for each child and the prevalence of myopia for each age group during each year was calculated. The mean spherical equivalent refraction and prevalence of myopia were compared between 2020 (after home confinement) and the previous 5 years for each age group.

Results: Of the 123 535 children included in the study, 64 335 (52.1%) were boys. A total of 194 904 test results (389 808 eyes) were included in the analysis. A substantial myopic shift (approximately -0.3 diopters [D]) was found in the 2020 school-based photoscreenings compared with previous years (2015-2019) for younger children aged 6 (-0.32 D), 7 (-0.28 D), and 8 (-0.29 D) years. The prevalence of myopia in the 2020 photoscreenings was higher than the highest prevalence of myopia within 2015-2019 for children aged 6 (21.5% vs 5.7%), 7 (26.2% vs 16.2%), and 8 (37.2% vs 27.7%) years. The differences in spherical equivalent refraction and the prevalence of myopia between 2020 and previous years were minimal in children aged 9 to 13 years.

Conclusions and relevance: Home confinement during the COVID-19 pandemic appeared to be associated with a significant myopic shift for children aged 6 to 8 years according to 2020 school-based photoscreenings. However, numerous limitations warrant caution in the interpretation of these associations, including use of noncycloplegic refractions and lack of orthokeratology history or ocular biometry data. Younger children's refractive status may be more sensitive to environmental changes than older ages, given the younger children are in a critical period for the development of myopia.

Conflict of interest statement

Conflict of Interest Disclosures: None reported.

Figures

Figure 1.. Spherical Equivalent Refraction (SER) Distribution in Primary School Students Aged 6 to 13 Years

The number of eyes per year with certain SER is plotted at 6 consecutive years for different age groups (6-13 years). The vertical line in each distribution represents the mean. At age 6 to 8 years, the crest as well as the mean (vertical line) in 2020 were shifted to the left compared with previous years, indicating a myopic shift of SER in 2020. For children aged 9 to 13 years, no clear myopic shift was observed across the 6 years.

Figure 2.. Mean Spherical Equivalent Refraction (SER) for Primary School Students Aged 6 to 13 Years During the 6 Years of Screenings

Substantial decreases of SER in 2020 were noted for children aged 6 to 8 years compared with previous years. Overall, girls tended to be more myopic than boys at the same age, while the right eye tended to be more myopic than the left eye. Whiskers indicate SEM.

Figure 3.. Prevalence of Refractive Error for Primary School Students Aged 6 to 13 Years During the 6 Years of Screenings

The prevalence of mild myopia increased in 2020 compared with previous years in children aged 6 to 8 years. Mild myopia: −3 diopters (D)  −0.5 D.