Spatiotemporal evolution of corneal biomechanical properties after cross-linking based on optical coherence elastography

Purpose To characterize the spatiotemporal evolution of corneal biomechanical properties after corneal cross-linking (CXL) using optical coherence elastography (OCE), with particular emphasis on regional changes in a hemicorneal partial-CXL model and temporal responses to standard and accelerated CXL (ACXL). Methods A silicone corneal phantom was constructed for system validation. Seven New Zealand white rabbits underwent hemicorneal partial-CXL in both eyes to investigate regional biomechanical changes. In addition, 11 rabbits received standard CXL or ACXL in contralateral eyes. OCE measurements were performed before and after treatment, and Corvis ST was additionally performed for complementary biomechanical assessment. Results OCE identified spatial biomechanical heterogeneity and quantified regional and temporal changes after CXL. In the hemicorneal partial-CXL model, linear mixed-effects analysis demonstrated a significant region-by-time interaction ( P < 0.001). The OCE-derived elastic modulus in the treated region was significantly higher than that in the untreated region at all postoperative time points ( P < 0.001). Compared with baseline, the treated region increased by 38.6%, 31.1%, and 56.8% at 1 week, 2 weeks, and 1 month, respectively, while the untreated region remained stable. The elastic modulus exhibited a temporal remodeling pattern characterized by an early increase, a mild decline at the intermediate stage, and a subsequent increase. Standard CXL and ACXL showed similar time-dependent biomechanical changes, with no significant differences between protocols at corresponding postoperative time points. Conclusion OCE revealed spatial heterogeneity and dynamic remodeling of corneal biomechanics after CXL. These findings support OCE as a tool for spatially resolved and longitudinal evaluation of CXL-induced biomechanical changes and provide a basis for future personalized CXL strategies.