Comparative effectiveness of orthokeratology versus highly aspherical lenslets in slowing myopia progression: a retrospective study

BACKGROUND: To compare the axial length (AL) elongation between orthokeratology (OK) and highly aspherical lenslets (HAL) in children with myopia. METHODS: This retrospective study included children with spherical equivalent refraction (SER) ranging from - 0.50 to - 9.00 D who were treated with OK lenses or HAL spectacles. Propensity score matching (PSM) was performed to balance baseline characteristics, including age, SER, sex, and baseline AL. The primary outcome was the 12-month AL elongation. Subgroup analyses were conducted according to age (8-9, 10-11, and 12-14 years) and refractive error categories (mild: - 0.50 to - 3.00 D; moderate: - 3.00 to - 5.00 D; high: - 5.00 to - 9.00 D). RESULTS: After PSM, 3,122 matched pairs (n = 6,244) with balanced baseline characteristics were included. Overall, OK group had greater AL elongation over 12 months than the HAL group (0.20 ± 0.18 mm vs. 0.15 ± 0.17 mm; P < 0.001). In age-stratified analyses, the OK group demonstrated greater AL elongation than the HAL group among younger children, including those aged 8-9 years (0.26 ± 0.18 mm vs. 0.19 ± 0.18 mm; P < 0.001) and 10-11 years (0.17 ± 0.17 mm vs. 0.12 ± 0.17 mm; P < 0.001). By contrast, no significant between-group difference was observed in children aged 12-14 years (P = 0.305). SER-stratified analyses revealed a refractive-error-dependent pattern. In children with mild myopia (- 0.50 to - 3.00 D), the OK group demonstrated greater AL elongation than the HAL group (P < 0.001). By contrast, among children with high myopia (- 5.00 to - 9.00 D), the OK group had lower AL elongation than the HAL group (P < 0.001), while no significant difference was observed for moderate myopia (P = 0.950). Subgroup analyses were performed using a propensity score-matched cohort. CONCLUSIONS: HAL were associated with less AL elongation in younger children and those with mild myopia, whereas OK lenses were associated with less AL elongation in children with high myopia. No significant differences between treatment modalities were observed in children with moderate myopia or in older children.