ABSTRACT
Purpose : To explore whether the COVID-19 lockdown increased the incidence of myopia among age-school children. Methods : Retrospective study recruiting children aged 5-12. Selection: random. Inclusion criteria: healthy children presenting for an eye exam since 2016. Exclusion criteria: presence of ocular comorbidities other than refractive error, spherical equivalent (SE) less than -4D or greater than +4D, BCVA less than 20/20, blepharoptosis, media opacities, corneal or retinal dystrophies, strabismus, amblyopia, nystagmus, or concurrent therapy with atropine 0.01%. Outcome measure: age measured in months, SE of the right eye (RE) measured in diopters (D) under cycloplegia (cyclopentolate 1%). Statistical analysis: ANOVA, Chi-square, Tukey's test. Significance: p < .05. Results : A total of 803 children. In the years prior to COVID-19, the mean SE ± SD diopters in the RE: 0.54 ± 1.49 D in 2016 (n = 160), 0.43 ± 1.84 D in 2017 (n = 145), 0.34 ± 1.41 D in 2018 (n = 152), 0.35 ± 1.75 D in 2019 (n = 166) (ANOVA, p = .659) (Fig. 1). In 2021 (n = 180), the mean SE was -0.08 ± 1.44 D (ANOVA, p = .005). Using the Tukey's test, the mean SE of 2021 changed by -0.619 D 95% CI [-1.091, -0.147] and -0.501 D 95% CI [-0.986, -0.016] as compared to the SE of 2016 and 2017, respectively (Fig. 2). Mean age was comparable in all groups (ANOVA, p = .307). The decrease of the mean SE of the 2021 group corresponds to an increase in the percentage of myopes (≤-0.5D) and a decrease in the percentage of hyperopes (≥ 2D). Myopes represent the 24.10% of children aged 60-96 months, and 63.86% of children aged 97-144 months. Hyperopes represent 9.64% of children aged 60-96 months, and 6.02% of children aged 97-144 months. This represents a statistically-significant increase in the number of myopes (Chi-square, p = .016) and decrease in the number of hyperopes (Chi-square, p = .001), as compared to the previous years (2016- 2019). Conclusions : This retrospective study shows a statistically-significant decrease in the mean SE in children aged 5-12 in the year following the COVID-19 lockdown (2021). The percentage of myopes has increased significantly, while the percentage of hyperopes has decreased. Children aged 8-12 years showed the greatest refractive change. The lifestyle changes imposed by the lockdown were likely responsible for the increased prevalence of myopia observed in 2021.