Corrected Percentile Curves to Track Myopisation-The Anyang Childhood Eye Study

Many reports in the literature have proposed the use of percentile curves for tracking ocular growth and monitoring myopic development. Recently, this practice has been criticised, particularly its inability to accurately track myopia onset and progression due to the inclusion of multiple refractive groups. This work assesses the validity of this criticism and proposes corrected curves tailored to specific refractive development trajectories.

The longitudinal biometric data of 1999 Chinese schoolchildren (10,766 measurements) in the Anyang Childhood Eye Study were analysed. Children were categorised into emmetropic and myopic subgroups based on the progression of their cycloplegic spherical equivalent (SE) refractive error. Percentile curves were generated for the axial length (AL), axial growth (dAL), axial length/corneal radius (AL/CR) ratio and cycloplegic SE using the Lambda-Mu-Sigma (LMS) method, stratified by sex and refractive group.

Distinct percentile curves for emmetropic and myopising eyes revealed significant differences compared with traditional population-based curves, confirming that whole-population curves underestimate myopia risk and overestimate treatment effects. Girls demonstrated greater myopic progression and axial elongation than boys. SE percentile curves, stratified by age of myopia onset, were presented to estimate progression trajectories.

This study presents percentile curves for ocular biometry and refractive error to enhance the ability to detect early myopic changes and monitor myopia control interventions. Recommendations include using SE curves based on cycloplegic refraction as the primary reference, developing sex- and region-specific models and avoiding reliance on AL alone.