A new analysis suggests the prevalence of myopia among children decreased and mean SER returned to the pre-pandemic levels after the lift of home confinement in China.
Changes in the prevalence of myopia in school-aged children 1 year after home confinement during the COVID-19 pandemic in China suggest refractive development in children may be susceptible to environmental changes.1
Compared with home confinement in 2020, cross-sectional data showed the prevalence of myopia among children 6 to 8 years old decreased in 2021 screenings, with the mean spherical equivalent refraction returning to pre-pandemic levels.
“Hence, this investigation supports that the 6- to 8-year age range is a critical period for myopia development, and the findings suggest targeting the window for myopia control,” wrote the investigative team.
The team, led by Xuehan Qian, MD, PhD, Department of Strabismus and Pediatric Ophthalmology, Tianjin Medical University Eye Hospital, previously conducted a study in 2020 on the association of home confinement with refractive development in school-aged children. Their findings indicated significantly greater prevalence compared with pre-pandemic years and a greater susceptibility to environmental change that influences ocular development.
However, their findings could not address whether the increased prevalence of myopia would persist among cohorts screened in post-pandemic years as they age. Investigators conducted additional screening in March 2021, alongside routine annual screening in September 2021. The population of schoolchildren aged 6 - 13 years from 10 elementary schools in Feicheng, China was screened annually since 2015.
Investigators obtained noncycloplegic refractive information using the Spot Vision photoscreener, to determine differences in SER and the prevalence of myopia between 2020 to 2021. Each child’s SER was recorded, and the team calculated the annual prevalence of myopia for each age group.
Examination results of 325,443 children (650,886 eyes) were included in the study. The sample consisted of 167,152 boys (51.4%) and 158,291 girls (48.6%) aged 6 to 13 years. According to the data, the mean SER per age group obtained during the March 2021 screenings was significantly higher than during 2020.
Data showed a significant higher SER was reported among children aged 6 years (0.42 diopters [D]; (P <.001), 7 years (0.41 D; P <.001), and 8 years (0.33 D; P <.001). This was an average increase of 0.39 D across age groups. Investigators noted the slight increase of mean SER in children aged 9 to 13 years was not significant relative to the increase among those 6 to 8 years.
Upon analysis of myopia prevalence, the findings suggest a significantly lower rate of myopia among children aged 6 to 8 years in 2021 than in 2020, particularly for the March 2021 screening (age 6: 7.9% vs. 12.5% [P < .001]; age 7 years: 13.9% vs 26.2% [P < .001]; age 8 years, 29.5% vs 37.2% [P < .001]). A decrease in myopia prevalence was observed in children age 9 to 10 and 13 years, but again, its magnitude was not comparable to the difference observed in younger children.
Based on this analysis, investigators believe the decrease in myopia prevalence was directly associated with the lift of home confinement and a return to a normal learning and living environment.
“When school-aged children returned to normal living and learning environments, the prevalence of myopia in the 6- to 8-year age group in post-pandemic screenings accordingly returned to the pre-pandemic levels, indicating that the myopia burden associated with the pandemic was temporary and alleviated by resumption of normal activities,” investigators wrote.