COVID-19 Lockdowns Linked to Early Myopic Shift

A large population-based study of more than 70,000 Chinese children ages six and younger found a significant myopic shift and increased premyopia prevalence during COVID-19 lockdowns in 2020. Published in Scientific Reports, the paper suggests reduced outdoor exposure, altered lighting conditions and confined visual environments may have disrupted early emmetropization, highlighting the importance of early monitoring and prevention strategies. Photo: Getty Images. Extensive evidence supports the awareness that increased outdoor activity in school-aged children reduces the risk of incident myopia and slows progression. Less is known about children ages three and under, who are undergoing rapid ocular growth and emmetropization. In the aftermath of COVID-19, home confinement and reduced outdoor time could factor strongly into early myopic shifts in this population, which led a group of Chinese researchers to further investigate. According to their findings, which were recently published in the journal Scientific Reports, a significant myopic shift did occur in 2020, in accordance with the confinement period. The cross-sectional, population-based study included 70,490 children up to age six in China, from 2018 to 2023. Researchers performed annual refractive screenings and trends were analyzed in mean spherical equivalent (SE) and premyopia prevalence (SE between -0.5D and +0.75D). They found that, between 2018 and 2019, the SE in children across all age groups remained stable. During the same period, the premyopia prevalence was between 51% and 78%. However, in 2020, all age groups showed a significant myopic shift. The study authors report the mean SE decreasing by 0.36D ±0.56D compared to 2019. Specifically, for the one-year-old group, the SE was 0.14D ±0.75D; for the two-year-old group, it was 0.07D ±0.42D; for the three-year-old group, it was 0.08D ±0.50D; for the four-year-old group, it was 0.04D ±0.56D; for the five-year-old group, it was 0.08D ±0.53D; and for the six-year-old group, it was -0.01D ±0.46D. The prevalence of pre-myopia reached its peak in all age groups in 2020 (80.3% in the one-year-old group, and exceeding 94% in the two- to six-year-old groups), showing a significant increase compared to 2018 to 2019. In response to the observed shifts coinciding with the period of reduced outdoor activity, the authors wrote, “Even among infants under one year old, who have limited exposure to near work, the significant SE decline suggests that subtle changes in visual stimuli and lighting conditions during confinement may disrupt normal refractive development. Additionally, confined spaces may increase peripheral hyperopic defocus, further promoting myopic shifts. Previous studies have shown that natural, full-spectrum light inhibits excessive axial elongation,while low-intensity indoor lighting accelerates it, potentially contributing to the observed refractive changes.” In light of these findings, the researchers call for public health strategies that prioritize access to outdoor environments to protect early refractive development, including ensuring kindergarten routines have at least two hours of daily outdoor activities.  They noted potential limitations, such as the use of non-cycloplegic refractions and lack of direct measures of outdoor exposure, screen time, or near-work duration. “Therefore, the observed refractive changes during 2020 cannot be causally attributed to reduced outdoor activity alone,” they wrote. “Future research should explore the long-term refractive outcomes of children affected by pandemic-related lifestyle changes, with a focus on those with early-onset premyopia.”In conclusion, the authors wrote that their study demonstrates a clear association between reduced outdoor activity and increased premyopia prevalence in young children, with the greatest impact on those under three years of age. “These findings reveal the importance of early myopia prevention strategies and monitoring refractive development from infancy. As societies recover from the pandemic, prioritizing visual health in young children will be critical in addressing the global burden of myopia.”Click here for the journal source. Xu L, Zhang Y, Yang C. et al. Age-dependent and reversible refractive changes in 0–6 years old children associated with reduced outdoor activity: A six-year community-based study. Sci Rep. January 19, 2026. [Epub ahead of print]. This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.