Improved control efficacy of a novel aspherical orthokeratology lens compared with the traditional three-zone spherical lens in a single-blind randomized clinical trial.

Purpose: Orthokeratology lenses slow myopia progression by over 50% on average. Efficacy and optical outcomes of aspherical and spherical orthokeratology lens designs in controlling myopia progression are compared, focusing on axial length (AL), choroidal thickness (CHT), and relative peripheral refractive errors.

Methods: A multicenter, single-blind, randomized controlled trial was conducted in Sichuan, China (2022-2023), with 30 participants aged 8-13 (mean age 10.8 ± 1.8 years; 70 % male). Inclusion criteria embraced refractive errors between -0.75 and -6.00 D. Each eye was randomly assigned to a spherical or aspherical lens. Measurements included AL and central corneal thickness and retinal defocus at baseline and 3, 6, 9, and 12 months.

Results: No baseline differences were observed between groups (P > 0.05). Throughout the 12 months, axial length (AL) increases were reported as 0.04 ± 0.18 mm and 0.25 ± 0.23 mm in the aspherical and spherical groups, respectively (P < 0.001). The aspherical lens produced greater corneal reshaping (nasal: 65.67 μm vs. 61.23 μm, P = 0.008; temporal: 68.03 μm vs. 61.07 μm, P = 0.002) and less hyperopic defocus (RDV30-45 and RDV45-53; P < 0.001). The change in AL correlated positively with the change in RDV. No other significant between-group differences in CHT changes were observed (P = 0.203).

Conclusion: Aspherical orthokeratology lenses show superior control of axial length compared to spherical lens designs due to increased sagittal height and peripheral myopic defocus within 15°-45° of retinal eccentricity.