Effect of COVID-19 quarantine on refractive errors in children aged 5 – 12 years: a retrospective study

Purpose: the COVID-19 quarantine led children to spend significantly more time indoors on near-work activities and digital devices. This study aims to explore whether these lifestyle changes had any effect on the prevalence of myopia among children aged 5 – 12 years1-3 . Subjects, Materials and Methods: retrospective study conducted in Italy. Population: children aged 5 – 12. Selection: random. Inclusion criteria: healthy children presenting for a routine eye exam since 2016. Exclusion criteria: presence of ocular comorbidities other than refractive error, spherical equivalent 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, spherical equivalent (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). 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 [-1.091, -0.147] 95% C.I. and -0.501 D [-0.986, -0.016] 95% C.I. as compared to the SE of 2016 and 2017, respectively. 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 quarantine (2021). The percentage of myopes has increased significantly, while the percentage of hyperopes has decreased. Children aged 97 – 144 months showed the greatest refractive change. The lifestyle changes imposed by the quarantine led children to spend more time on near-work activities and digital devices, which are both known risk factors for the onset and progression of myopia. These lifestyle changes were likely responsible for the increased prevalence of myopia observed in the post-quarantine year