A Comparative Study of Atropine, Orthokeratology, and Combination Therapy for Axial Elongation in Children with Myopia.

Background/Objectives: Atropine and orthokeratology (OK) are used for childhood myopia control, but comparisons of atropine monotherapy, OK monotherapy, and combination therapy remain limited. This study compared 12-month axial length changes and the proportions of fast, intermediate, and slow progressors among these treatments. Methods: This retrospective study included 154 children followed for at least 12 months: 70 received atropine monotherapy, 64 received OK monotherapy, and 20 received combination therapy. Axial length changes at 6 and 12 months were analyzed using a linear mixed-effects model adjusted for age at treatment initiation, sex, baseline axial length and baseline spherical equivalent refractive error. Based on 12-month axial elongation, progression was classified as fast (≥0.30 mm), intermediate (0.15 to <0.30 mm), or slow (<0.15 mm). Results: At 12 months, mean axial elongation was 0.294 ± 0.209 mm, 0.238 ± 0.228 mm, and 0.160 ± 0.109 mm in the atropine, OK, and combination groups, respectively. The group-by-time interaction was significant (p = 0.006). No significant pairwise differences were observed at 6 months. At 12 months, axial elongation was significantly smaller in the combination group than in the atropine and OK groups (adjusted mean differences, 0.161 and 0.115 mm; 95% CI, 0.078-0.245 and 0.024-0.207; Holm-adjusted p < 0.001 and 0.027, respectively). There was no significant difference between the atropine and OK groups (p = 0.155). The pattern of progression differed among groups (p = 0.017), with fast progressors least frequent in the combination group (5.0% vs. 32.9% and 32.8%). Conclusions: In this observational cohort, combination therapy was associated with less axial elongation and fewer fast progressors than either monotherapy.