Ortho-K Study Finds Better AL Stabilization in Children with Higher Baseline Myopia, Older Age

Recent findings of ECD reduction, particularly in eyes with axial elongation, suggest that corneal endothelial monitoring may be prudent in ortho-K wearers. Photo: Dan Fuller, OD. Click image to enlarge. Change in axial length (AL) is a key parameter for assessing myopia progression and the efficacy of any interventions. Growing evidence suggests that changes in choroidal thickness may contribute to axial length reduction. Researchers in China recently evaluated the baseline biometric parameter characteristics of myopic children with significant axial length reduction (AL reduction group) and rapid progression (AL elongation group) during overnight orthokeratology (ortho-K) lens wear.They found that children with higher baseline myopia and older age showed relatively less AL growth after wearing ortho-K lenses. In children ages eight to 11, those with a longer baseline axial length (≥ 24.5mm) exhibited slower AL elongation during the first two years of ortho-K treatment. These results may be because higher degrees of myopia lead to a greater reduction in the diopter in the central corneal treatment zone and a greater increase in peripheral corneal refraction, inducing more peripheral retinal myopic defocus.The study, which was published in BMC Ophthalmology, retrospectively reviewed changes in ocular parameters in 164 children who completed one year of ortho-K treatment. The cohort was divided into AL reduction (n = 105, ≤ 0mm/year axial growth) and AL elongation (n = 59, ≥ 0.4mm/year axial growth) groups based on one-year axial length changes.Compared with those in the AL elongation group, children in the AL reduction group were older, had a higher degree of myopia, larger pupil diameter, deeper anterior chamber depth and lower corneal endothelial density. In the AL reduction group, the reduction was negatively correlated with white-to-white corneal diameter (WTW) and central corneal thickness (CCT). The research team proposed that the ratio between the changes of these two measurements may be useful for predicting AL reduction.“In the AL reduction group, the more pronounced thinning of the CCT may also be related to the degree of refractive correction and the design of orthokeratology lenses,” they wrote in their paper.After one year of follow-up, the researchers also found that endothelial cell density (ECD) decreased in both the AL reduction and elongation groups, with the AL elongation group showing an increase in anterior chamber depth and a decrease in corneal diameter. The endothelial cell loss in the elongation group was 1.95 times greater than that in the reduction group.“The greater ECD loss in the AL elongation group aligns with their concurrent WTW reduction, indicating that corneal radial tension may transmit axial stress to the endothelium. The greater ECD loss in the AL elongation group, coinciding with rapid axial growth, may reflect indirect mechanical stress on the corneal endothelium, although the direct causal pathways remain unclear,” the study authors wrote.Although the AL elongation group in this study showed more endothelial loss, the researchers noted that the ECD reduction may be due to a variety of factors (mechanical lens stimulation and age-related loss), requiring more corneal specular microscopy examinations. Click here for the journal source. Ai X, Zhang X, Wang R, Li Y. Baseline ocular biometrics in children with orthokeratology-induced axial length reduction or elongation. BMC Ophthalmol. 2025;25(1):498.This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.