Changes in corneal diameter in myopic children during 18 months randomly assigned to orthokeratology lenses or single‐vision spectacles

Abstract

AbstractPurpose: Orthokeratology lenses (OKL) have been shown to reduce axial length elongation in myopic children. OKL are costume fit, reverse geometry lenses. One of the parameters used to ensure lens fitting is the corneal diameter. The purpose of this study was to investigate changes in corneal diameter during 18 months in myopic children randomized to OKL or single‐vision spectacles (SVS).Methods: This study was an 18‐month 1:1 randomized, controlled trial of Danish myopic children aged 6–12 years with myopia ranging from 0.5 to 4.75 diopters (D) spherical component and refractive astigmatism ≤2.5 D. The intervention was orthokeratology lenses (OKL), while the control group received SVS. The outcome measure was corneal diameter (Pentacam HR, Oculus, Wetzlar, Germany).Results: A total of 37 right eyes were included, 23 (13 female) in the control group and 14 (9 female) in the intervention group. We found a significant change in corneal diameter in both the control group (difference in medians of 0.20 mm, p < 0.001, Wilcoxon signed‐rank test) and the intervention group (difference in medians of 0.175 mm, p < 0.001, Wilcoxon signed‐rank test). Furthermore, when comparing our 2 groups, we saw a significantly smaller increase in corneal diameter in the intervention group compared to the control group (difference in medians of 0.025 mm, p = 0.03, Mann–Whitney rank‐sum test).Conclusions: The corneal diameter significantly changes during 18 months in Danish children in both groups, however, the difference is significantly less during OKL treatment. The latter needs further clarification at this point. We can conclude, that to ensure correct OKL fitting in children close monitoring during OKL treatment is necessary.