Variations in Corneal Refractive Change Region After Orthokeratology Lens Wear

Purpose: This study analyzed 1-year longitudinal variations in the corneal refractive change (CRC) region after orthokeratology (Ortho-K) lens wear between vision shaping treatment (VST) and corneal refractive therapy (CRT) designs. Methods: A retrospective analysis was conducted on 148 patients with myopia (148 eyes) treated with Ortho-K lenses for 12 months at Beijing Tongren Hospital's myopia clinic from June 2020 to December 2022. Participants were divided into two groups: group A (74 eyes) who wore VST design Ortho-K lens, and group B (74 eyes) who wore CRT design lens. Data from the right eyes were collected. Measurements included tangential corneal topography maps, which were converted into refractive power maps to calculate the area, height, and volume of the CRC region. Measurements were taken at baseline and during follow-ups after lens wear. Changes in magnitude of the CRC region were analyzed for different Ortho-K lens designs. Results: No statistically significant difference in the height of the CRC region was observed between group A and group B on the first day of lens wear (P > 0.05). However, significant differences emerged at 1 month, 3 months, 6 months, and 1 year of wear (P < 0.001). For both groups, the height of the CRC region at these follow-up points showed significant differences compared to the first day of wear (P < 0.001). No significant differences were found between the two groups in the area of the CRC region at any time point (P > 0.05). The area of the CRC region decreased significantly by month 1 in the VST group while slightly rising in the CRT group, with no significant post-1-month fluctuations across the 12-month follow-up. The volume of the CRC region rose rapidly and then plateaued by 1 month. The axial length increased by 0.17 mm and 0.19 mm for group A and group B, respectively, after 6 months of lens wear. After 1 year, the axial elongation values were 0.26 mm and 0.28 mm for the 2 groups, with no statistically significant intergroup difference observed at either follow-up time point (P > 0.05). Conclusions: Orthokeratology induces measurable changes in the height and volume of the CRC region. Both parameters are important for evaluating myopia control outcomes, and our findings provide guidance for clinical lens selection. Translational Relevance: A mathematical model was applied to characterize dynamic corneal defocus changes. The results enable precise clinical practice, such as personalized lens configuration, efficacy prediction, and stratified management for orthokeratology patients.