Clinical outcomes and baseline factors associated with one-year axial elongation during orthokeratology wear in children: a retrospective study

Myopia has emerged as a major global public health concern, especially in Asia, with high myopia substantially increasing the risk of complications such as retinal degeneration and glaucoma. This study aimed to evaluate the efficacy of orthokeratology (Ortho-K) in controlling axial length (AL) elongation in myopic children over a one-year period and to identify baseline predictors of treatment response. This retrospective, single-group, pre-post control study included 122 children (244 eyes) with myopia who were fitted with orthokeratology lenses at Jiangyin People’s Hospital between January 2024 and December 2025 and completed one year of follow-up. Baseline data, including age, body mass index (BMI), spherical equivalent (SE), pupil diameter (PD), and axial length (AL) were collected. Changes in AL were analyzed using paired t-tests, Linear mixed-effects model analysis, and receiver operating characteristic (ROC) curve analysis were performed. The mean AL elongation after one year was 0.23 ± 0.15 mm. Linear mixed-effects model analysis of factors associated with one-year axial length growth revealed that baseline age (estimate = − 0.04, p < 0.001), baseline SE (estimate = 0.02, 0.004), baseline BMI (estimate = 0.01, p < 0.001), and baseline pupil diameter (estimate = − 0.08, p < 0.001) were independently associated with AL change. ROC curve analysis identified exploratory cutoff values associated with slower axial elongation during orthokeratology wear, including age 11.50 years (overall), axial length of 24.33 mm, and pupil diameter of 5.10 mm. Sex-stratified analysis suggested age-related differences, with corresponding cutoff values of 10.5 years for males and 11.5 years for females. Children undergoing orthokeratology showed a mean one-year axial elongation of 0.23 mm. Older age, higher baseline myopia, larger pupil diameter and BMI were associated with axial elongation during treatment, with notable sex differences. These findings may help inform individualized orthokeratology management in pediatric myopia.