Myopia prevalence was kept steady, despite increased screen time and hours spent indoors during COVID-19 lockdowns, amongst a group of preschool-age children in Taiwan, thanks to a program that promoted outdoor activities. The effect of the public intervention was reported in Ophthalmology.

The Yilan Myopia Prevention and Vision Improvement Program, launched in 2014, screens preschool children for ocular disorders and determines the prevalence of myopia. The current research reviewed the records of the program’s participants to evaluate its efficacy.

The overall prevalence of myopia among the 21,761 eligible patients was 10.7% for the whole cohort. It decreased significantly from 15.5% in 2014 to 13.5% in 2015 and 8.4% in 2016 and was relatively stable from 2016 through 2020 (P <.001). From 2014 to 2020, the total decrease of myopia prevalence was 5.2%.


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Myopia prevalence did not change significantly before and during the pandemic, despite increases in the portion of participants who did not spend at least 30 minutes in outside activities each weekday (50.5% in the prepandemic 2019 cohort to 54% in 2020) and in participants who spent at least 1 hour per weekday on screen-based devices (2019: 42.8%, 2020: 45.2%) and at least 2 hours per weekend day (2019: 35.3%; 2020: 38.5%).

The strategies included ensuring good classroom lighting and table height, avoiding prolonged near work activities, such as using screen-based devices, and encouraging outdoor activities for 2 hours daily.

Each fall, from August 2014 to December 2020, the bureau screened children aged 5 to 6 years with eye exams and questionnaires to collect demographic, medical and myopiagenic behavioral data. The program continued through the COVID-19 pandemic since there was no suspension of on-site classes in most schools in Taiwan before May 2021. The researchers excluded patients treated with orthokeratology.

Patients with myopia were more likely to be boys, have shorter exposure to the preventative strategies, have a caregiver with myopia and lower education levels, sleep less than 9 hours per night, spend more time on screen-based devices on weekdays, and less time outdoors on weekends.

Limitations of the study included potential for recall bias or variation in compliance. Researchers also noted that COVID-19 restrictions might have a delayed effect on myopia prevalence that have not yet been detectable.

Researchers report observing “several lines of solid evidence on the protective role of increased time outdoors.” The approach was associated with a decrease in myopia prevalence, which became stationary when most participants were fully exposed to the recommended interventions. In multivariable analysis, the researchers found that longer duration of preventative strategy exposure was associated with decreased preschool myopia.

Reference

Yang YC, Hsu NW, Wang CY, et al. Prevalence trend of myopia after promoting eyecare in preschoolers: a serial survey in Taiwan before and during the COVID-19 pandemic. Ophthalmol. Published online August 20, 2021. doi:10.1016/j.ophtha.2021.08.013