Predictive factors associated with axial length growth and myopia progression in orthokeratology

PURPOSE: To investigate the factors affecting axial length (AXL) growth and myopia progression in orthokeratology. METHODS: This prospective, observational study enrolled 28 new orthokeratology lens wearers from a contact lens clinic between March 2016 and March 2017. Among them, 32 eyes of 17 wearers who completed one year of follow-up were finally analyzed. All participants underwent central (C) and peripheral (nasal 30° [N30] and temporal 30° [T30]) AXL measurements as well as central and peripheral refraction, ocular aberrations, and corneal topography at baseline and every posttreatment visit. A generalized estimating equation (GEE) was used to assess the associations between AXL change and all independent variables in both eyes. RESULTS: The mean central AXL was 24.21 ± 0.60 mm and the mean baseline central spherical equivalent refractive error (SER) was −2.43 ± 0.97 diopters (D). Among all parameters that were significantly associated with AXL change in univariable GEE analyses, the baseline difference in AXL between C and N30 (β = −0.213, p < 0.001), baseline SER (β = −0.040, p < 0.033), posttreatment coma (β = −0.291, p < 0.031), third-order higher-order aberrations (HOAs) (β = −0.482, p < 0.001), and changes in second-order aberrations (β = 0.025, p = 0.027) at one year of follow-up were identified as significant factors in multivariable GEE analysis. CONCLUSIONS: The inhibition of AXL elongation and myopia progression in orthokeratology lens wear is significantly associated with the peripheral myopization and asymmetric optical changes mostly induced by third-order HOAs.