Subfoveal choroidal thickness and axial length changes with orthokeratology in bilateral anisomyopia

Abstract Purpose To investigate the change in subfoveal choroidal thickness (SFChT) in bilateral anisomyopic children undergoing orthokeratology (ortho‐k) over 2 years and the association with axial elongation (AE). Methods SFChT, axial length and refractive data from 26 bilateral anisomyopic subjects (aged 7–12 years) who participated in a 2‐year prospective orthokeratology study were analysed using generalised estimating equations and linear mixed models. Results SFChT in the more myopic eyes (MME) (at least 1.50 D more myopia than the fellow eye) became thicker (mean ± standard deviation change, 25 ± 20 μm) after 6 months of ortho‐k lens wear ( p < 0.001) and remained stable thereafter ( p ≥ 0.13), but no such change was observed in the less myopic eyes (LME) ( p ≥ 0.07). Combining data from both eyes, the baseline SFChT and SFChT change after 2 years of ortho‐k treatment were associated with 2‐year AE [generalised estimating equation (accounting for the inclusion of both eyes): β = 0.002, p = 0.03 and β = −0.005, p < 0.001, respectively]. Conclusions After 2 years of ortho‐k treatment, the increase in the SFChT occurred exclusively in the MME. Considering both eyes, greater SFChT thickening was associated with less eye growth.