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

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