Efficacy of Myopia Control by Orthokeratology Lenses is Associated with Changes in Total Corneal Higher Order Aberrations

Abstract

Purpose : Studies have shown a correlation between change in ocular higher order aberrations (HOA) and myopia control efficacy by orthokeratology lenses (OKL). This study investigated the correlation between changes in corneal HOA and treatment efficacy by OKL measured by change in axial length (AL).

Methods : An 18-months 1:1 randomized, controlled trial on 60 myopic children aged 6 to 12 years. The intervention was the aspherical base curve OKL Dreamlite® (CooperVision, San Ramon, California, USA), a four-zone reverse geometry lens with a 6 mm optic zone diameter, and 0.75 D compression factor, and the control-group used single-vision spectacles. For this sub-study, only data from the intervention group was used. Total corneal root mean square (RMS) HOA were measured with scheimpflug topography at baseline, days 3 and 7 and 1-, 3-, 6-, 9-, 12-, 15-, and 18-month follow-up. Four consecutive measures per eye were obtained at baseline, 6-, 12-, and 18-month follow-up. For the remaining follow-up visits, two or three measurements were obtained. Only measurements with the status “OK” and error “0” were included in the analysis. AL at follow-up was adjusted for the reduction in central corneal thickness caused by OKL. Lenstar LS900 was used to measure AL and central corneal thickness. Five to six consecutive measurements per eye were obtained. For all variables, data from each eye at each visit were averaged for analysis. Nested mixed models were used to allow inclusion of data from both eyes and conducted in Stata software. Baseline age and baseline spherical equivalent refractive error (SER) were included to adjust for possible confounding effects. The significance level was set to 0.05.

Results : Change in RMS HOA and baseline SER were significantly inverse correlated to change in AL (p = 0.023 and p < 0.001). The correlation between change in RMS HOA and change in AL was stable during all 18 months of follow-up whereas the strength of the correlation between baseline SER and change in AL weakened over time. There was a significant inverse correlation between baseline SER and change in RMS HOA (p < 0.001, r² = 0.45). There was no statistically correlation between baseline age and change in AL (p = 0.27).

Conclusions : The more total corneal RMS HOA induced by the OKL the better the myopia control efficacy measured by change in axial length. Lower baseline SER induced more RMS HOA.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.