Short-Term Effects of Orthokeratology Treatment Zone Decentration on Choroidal Thickness and Vasculature

Purpose: This study investigated the short-term effects of orthokeratology (ortho-K) treatment zone decentration (TZD) on choroidal thickness (ChT) and vasculature in children with myopia. Methods: Children aged 8 to 12 years with myopia undergoing ortho-K were recruited from the Tianjin Medical University Eye Hospital. Subfoveal ChT, choroidal vascularity index, and choriocapillaris perfusion area were assessed using optical coherence tomography and optical coherence tomography angiography at baseline and after 1 month of lens wear. Corneal topography was used to quantify the TZD. Results: After 1 month of ortho-K, ChT significantly increased by 17.74 ± 8.89 µm and 18.25 ± 8.98 µm in the low and moderate myopia groups, respectively (P < 0.05). The choriocapillaris perfusion area also increased by 0.013 ± 0.014 mm2 and 0.017 ± 0.017 mm2, respectively, although no significant change was observed in the choroidal vascularity index. Multiple regression analysis revealed that changes in ChT were significantly correlated with baseline spherical equivalent and the magnitude of the TZD (all P < 0.05). However, there was no significant correlation between the direction of decentration and quadrant-specific changes in ChT. Conclusions: A larger TZD was significantly associated with a greater increase ChT after 1 month of ortho-K treatment, particularly in children with relatively high myopia. Translational Relevance: Orthokeratology treatment zone decentration is associated with choroidal thickening during 1-month orthokeratology treatment. This early change may provide a new perspective for evaluating its potential role in long-term myopia control.