Baseline ocular biometrics in children with orthokeratology-induced axial length reduction or elongation.

Purpose: To determine the baseline ocular biometrics in children with axial length reduction after orthokeratology for better myopia control.

Methods: Changes in ocular parameters in 164 subjects who completed one year of Ortho-K treatment were retrospectively reviewed. The subjects were divided into AL reduction (n = 105, ≤ 0 mm/year axial growth) and AL elongation (n = 59, ≥ 0.4 mm/year axial growth) groups based on 1-year axial length changes.

Results: Compared with those in the AL elongation group, children in the AL reduction group were older (p < 0.001), had a higher degree of myopia(p < 0.001), larger pupil diameter (p < 0.001), deeper anterior chamber depth (p = 0.007), and lower corneal endothelial density (p < 0.001). In the AL reduction group, the reduction was negatively correlated with WTW and CCT changes (ρ=-0.346, p < 0.001). Endothelial cell loss in the elongation group was 1.95 times greater than that in the reduction group (44.239 ± 79.629 vs.22.646 ± 79.038 cells/mm²).

Conclusions: Baseline age, degree of myopia, pupil diameter, and anterior chamber depth were associated with the efficacy of orthokeratology in controlling axial length. The ΔWTW/ΔCCT ratio may be useful for predicting AL reduction. Regular examination of the corneal endothelium in children with rapid axial length elongation is recommended.