The impact of COVID-19 home confinement on axial length in myopic children undergoing orthokeratology

Understanding the impact of home confinement on axial length in myopic children undergoing orthokeratology (OK) treatment facilitates the management of myopia control during coronavirus disease 2019 (COVID-19) lockdown.The outbreak of COVID-19 and the corresponding home confinement measures have brought a considerable challenge to myopia control. The study aimed to investigate the influence of home quarantine on axial length in myopic children with OK treatment.Axial length measurements during and before COVID-19 home confinement were retrospectively collected from the myopic children treated with OK, and the children were prospectively followed up after finishing the quarantine. The monthly axial length growth before, during and after confinement was calculated and compared in the full dataset and subgroups stratified by age. Influencing factors for monthly axial length growth during confinement were analysed.Ninety-two myopic children with OK treatment were enrolled in this study. In the full dataset, covariates adjusted (gender, time interval, baseline axial length and age) monthly axial length growth during confinement was not significantly different from that before (P = 0.213) or after the home confinement (P = 1.000). Multiple linear regression showed that the monthly axial length growth during confinement was negatively correlated with age (P = 0.002). Subgroup analysis based on age demonstrated that the adjusted monthly axial length growth was not significantly different among three periods (P > 0.05) for younger children. For children older than 12-year-old, the adjusted monthly axial length growth during home confinement was significantly slower than before the confinement (P = 0.011), but not the monthly axial length growth after the confinement (P = 1.000).COVID-19 home confinement does not increase the myopic axial length elongation in children with OK treatment.