Development of Myopia Found to Accelerate in Young Schoolchildren Amid Pandemic

Environmental changes amid COVID-19 may have accelerated the development of myopia (nearsightedness) in young schoolchildren, according to study findings published in JAMA Ophthalmology

With more than 220 million school-aged children and adolescents in China confined to their homes due to the COVID-19 pandemic, there have been concerns over whether reduced outdoor activities and increased digital screen time may worsen the global burden of myopia.

In fact, a recent cross-sectional study of school-based photoscreenings in Chinese children aged 6 to 8 years uncovered a significant myopic shift during the pandemic compared with previous years. With myopia defined by a spherical equivalent refraction (SER) of –0.50 diopters (D) or less, these populations exhibited a growing myopia risk of –0.3 D and an increased prevalence of 10% to 16% in 2020.

“The study results indicated that it is likely only young schoolchildren, being in the critical period of myopia development, were sensitive to certain environmental changes during this period,” noted researchers.

Seeking to further assess changes in the development of myopia among young schoolchildren during the pandemic, they conducted an observational study that longitudinally monitored 2114 students from grade 2 to grade 3 of 12 primary schools in Guangzhou, China.

Participants were placed in 2 groups:

• The exposure group (n = 1054), grade 1 students in November and December 2018 who were assessed from grade 2 (November and December 2019) to grade 3 (November and December 2020) during the COVID-19 pandemic
• The nonexposure group (n = 853), students in grade 2 in November and December 2018 who were assessed from grade 2 (November and December 2018) to grade 3 (November and December 2019) prior to the pandemic

Primary outcomes included changes in cycloplegic SER, axial length (AL) elongation, and myopia incidence from grade 2 to grade 3. Children with emmetropia and SER greater than −0.50 D and less than or equal to +0.50 D (lower than the age-normal) were identified in the study to estimate the future development of myopia.

From grade 2 to grade 3, participants of the exposure group experienced a significant 0.36 D (95% CI, 0.32-0.41; P < .001) more myopic shift of SER and 0.08 mm (95% CI, 0.06-0.10; P < .001) greater AL elongation than those in the nonexposure group. Moreover, incidence of myopia was indicated to 7.9% higher in the exposure group vs the nonexposure group during this time frame (95% CI, 5.1%-10.6%; P < .001).

Specific to grade 3 students, prevalence of myopia increased substantially from 13.3% in November and December 2019 to 20.8% in November and December 2020 (difference, 7.5%; 95% CI, 4.3%-10.7%; P < .001).

In assessing risk, the proportion of children without myopia and with SER greater than −0.50 D and less than or equal to +0.50 D increased from 31.1% to 49.0% (difference, 17.9%; 95% CI, 13.3%-22.4%; P < .001).

“In this study, development of myopia increased during the COVID-19 outbreak period in young schoolchildren in China. Consequently, myopia prevalence and the proportion of children without myopia who were at risk of developing myopia increased,” concluded the study authors. “Future studies are needed to investigate long-term changes in myopia development after the COVID-19 pandemic.”

Reference

Hu Y, Zhao F, Ding X, et al. Rates of myopia development in young Chinese schoolchildren during the outbreak of COVID-19. JAMA Ophthalmol. Published online September 16, 2021. doi:10.1001/jamaophthalmol.2021.3563