Prevalence of Myopia in Children Before, During, and After COVID-19 Restrictions in Hong Kong

Abstract

ImportanceChildhood myopia increased during the COVID-19 pandemic. Limited evidence exists about whether myopia development was reversed or worsened after the lockdown.ObjectiveTo determine the prevalence of myopia and its associated factors before, during, and after COVID-19 restrictions.Design, Setting, and ParticipantsThis population-based, repeated cross-sectional study evaluated children aged 6 to 8 years from the Hong Kong Children Eye Study between 2015 and 2021 in 3 cohorts: before COVID-19 (2015-2019), during COVID-19 restrictions (2020), and after COVID-19 restrictions were lifted (2021).ExposuresAll the children received ocular examinations, including cycloplegic autorefraction and axial length. Data about the children’s lifestyle, including time spent outdoors, near-work time, and screen time, were collected from a standardized questionnaire.Main Outcomes and MeasuresThe main outcomes were the prevalence of myopia, mean spherical equivalent refraction, axial length, changes in lifestyle, and the associated factors over 7 years. Data were analyzed using descriptive statistics, logistic regression, and generalized estimating equations.ResultsOf 20 527 children (mean [SD] age, 7.33 [0.89] years; 52.8% boys and 47.2% girls), myopia prevalence was stable from 2015 to 2019 (23.5%-24.9%; P = .90) but increased to 28.8% (P < .001) in 2020 and 36.2% (P < .001) in 2021. The mean (SD) time spent outdoors was much lower in 2020 (0.85 [0.53] h/d; P < .001) and 2021 (1.26 [0.48] h/d; P < .001) compared with pre–COVID-19 levels (1.40 [0.47]-1.46 [0.65] h/d). The trend was reversed for total near-work time and screen time. High myopia prevalence was associated with the COVID-19 pandemic (odds ratio [OR], 1.40; 95% CI, 1.28-1.54; P < .001), younger age (OR, 1.84; 95% CI, 1.76-1.93; P < .001), male sex (OR, 1.11; 95% CI, 1.03-1.21; P = .007), lower family income (OR, 1.05; 95% CI, 1.00-1.09; P = .04), and parental myopia (OR, 1.61; 95% CI, 1.52-1.70; P < .001). During the pandemic, mean (SD) near-work and screen times in children from lower-income families were 5.16 (2.05) h/d and 3.44 (1.97) h/d, more than from higher-income families (4.83 [1.85] and 2.90 [1.61] h/d, respectively).Conclusions and RelevanceThe findings of this cross-sectional study revealed that after COVID-19 restrictions were lifted in Hong Kong, myopia prevalence among children was higher than before the pandemic, and lifestyle did not return to pre–COVID-19 levels. Younger children and those from low-income families were at a higher risk of myopia development during the pandemic, suggesting that collective efforts for myopia control should be advocated for these groups.

Low-Concentration Atropine Eyedrops for Myopia in Children—Reply

“…Third, the 2-year myopia incidence in our study was higher than that in the pilot study, which could be attributed to the surge in myopia incidence during the COVID-19 pandemic. Recent reports have shown that myopia increased in children during the pandemic, even after the restrictions were lifted . Although the proportion of children enrolled before the pandemic was similar among the 3 groups, our study period (2017-2022) spanned the pandemic, during which time myopia incidence increased, which could have diminished treatment effectiveness.…”

Predicting the onset of myopia in children by age, sex, and ethnicity: Results from the CLEERE Study

“…Changes in children's behavior imposed by COVID restrictions implicate both, with some indication from multivariate analysis of greater effects from limited time outdoors compared with increased near work. [45][46][47] Importantly, neither CLEERE nor other predictive models include these time-varying factors in the calculation of probability of myopia onset. More children may be at risk due to changes in behavior, but once a particular level of refractive error is reached, the probability of myopia onset by sex and ethnicity may not have changed substantially.…”

“…The likely source of increased prevalence is time-varying environmental factors such as increased near work, decreased time outdoors, or some combination of the two. Changes in children's behavior imposed by COVID restrictions implicate both, with some indication from multivariate analysis of greater effects from limited time outdoors compared with increased near work 45–47 . Importantly, neither CLEERE nor other predictive models include these time-varying factors in the calculation of probability of myopia onset.…”

COVID-19 and children’s eyes

“…The results of a study in East Asia on more than 20 500 children showed that the myopia prevalence in children was increased as compared to that before the pandemic, and that lifestyles did not revert to those of the pre-COVID-19 era. During the pandemic, younger children and those from lower income were at a higher risk of myopia development [ 27 ] .…”