Effects of Orthokeratology Versus Single-Vision Spectacles on Choroidal Structure and Microcirculation in Adolescents With Myopia

OBJECTIVE: To compare the longitudinal effects of single-vision spectacles (SV) and orthokeratology (OK) lenses on choroidal structure and microcirculation in adolescents with myopia, and to analyze differences in responses between the two correction modalities. METHODS: This prospective, nonrandomized cohort study enrolled myopic patients aged 8 to 15 years. Axial length (AL), spherical equivalent refraction (SE), choroidal thickness (ChT), and three-dimensional choroidal vascularity index (3D-CVI) in nine macular sectors within concentric rings of 1, 3, and 6 mm in diameter were measured at baseline and at 1 week, 1 month, 3 months, 6 months, and 1 year after lens wear. Within-group and between-group differences were analyzed. RESULTS: A total of 116 myopic patients aged 8 to 15 years were enrolled, including 62 in the SV group and 54 in the OK group. After 1 year, AL elongation in the OK group (0.101±0.032 mm) was significantly smaller than that in the SV group (0.393±0.035 mm; P<0.001), and the change in SE (-0.444±0.251 D) was also significantly smaller than that in the SV group (-0.863±0.372 D; P<0.001). Between-group differences in AL emerged from 1 month (P<0.001), and differences in SE emerged from 3 months (P<0.001). In the OK group, ChT increased across sectors during the first 1 to 3 months, followed by partial fluctuation and regression thereafter, whereas 3D-CVI generally increased during months 3 to 6 with mild later fluctuation. In the SV group, most sectors showed statistically significant differences, except for the outer inferior sector, but changes lacked a consistent trend; for 3D-CVI, significant differences were observed in several sectors, likewise without a consistent trend. Except at 1 week, increases in ChT and 3D-CVI in almost all macular sectors at subsequent time points were significantly greater in the OK group than in the SV group (most P<0.05). CONCLUSIONS: Compared with SV, OK lenses suppress AL elongation and SE progression. There are increases in ChT and 3D-CVI associated with this suppression, suggesting that ChT and 3D-CVI may serve as biomarkers for evaluating the efficacy of myopia-control interventions and supporting further investigation of their role in mechanism of myopia control.