Comparison of trial lens-fitting and software-fitting in orthokeratology for myopia control in children with high corneal eccentric value.

Purpose: To compare the safety and efficacy of the trial lens-fitting and software-fitting in orthokeratology for myopia control in children with high corneal eccentric value.

Methods: Myopic children with high corneal eccentric value (≥0.65) receiving treatment for orthokeratology from July 2020 to January 2022 were included in this retrospective study. Only the right eyes were included. The participants were allocated into two groups: the trial lens-fitting group (n = 41) and the software-fitting group (n = 48). The uncorrected visual acuity (UCVA), corneal topography, and ocular health (Efron grading scales) were recorded at baseline, one week, two weeks, one, three, six, and 12 months afterthe initiation of lens wear. The axial length and endothelial cell density were assessed at baseline and after 12 months of lens wear.

Results: The success rate of the first fit in the software-fitting group and trial lens-fitting group reached 98 % and 95 %, respectively. The difference in UCVA and corneal staining were statistically insignificant between the two groups during all visits. The software-fitting group exhibited a smaller treatment zone size (radius 1.69 ± 0.21 mm vs 1.81 ± 0.16 mm, p = 0.004; area 9.13 ± 2.15 mm² vs 10.36 ± 1.82 mm², p = 0.005) and less decentration (0.58 ± 0.31 mm vs 0.74 ± 0.39 mm, p = 0.036) compared with the trial lens-fitting group. There were no significant differences in axial elongation (0.15 ± 0.12 mm vs. 0.17 ± 0.14 mm, p = 0.534) or changes in endothelial cell density (-36.63 ± 99.37/mm² vs - 13.71 ± 87.72/mm², p = 0.256) between the software-fitting group and the trial lens-fitting group at one-year follow-up visit.

Conclusion: Both fitting methods were effective and safe. However, the software-fitting method resulted in a smaller treatment zone size and less decentration.