Longitudinal densitometric and biomechanical changes following accelerated epithelium-off corneal cross-linking for keratoconus

To characterize longitudinal changes in Scheimpflug corneal densitometry and Corvis ST biomechanical parameters after accelerated epithelium-off corneal cross-linking (CXL) for keratoconus (KC) and to explore their postoperative associations. This retrospective observational study included 35 eyes of 22 patients with progressive KC who completed 1 year of follow-up after accelerated epithelium-off CXL. Corrected distance visual acuity (CDVA), endothelial cell density (ECD), corneal tomography, Scheimpflug densitometry, and Corvis ST printouts were used to extract layer-specific densitometry, Belin/Ambrosio indices, and dynamic deformation parameters. Anterior stromal densitometry in the 0.0–2.0 mm and 2.0–6.0 mm annuli increased markedly at 1 month after CXL and then declined gradually. In the 2.0–6.0 mm annulus, 1-month anterior densitometry correlated with Ambrosio relational thickness-horizontal (ARTh), whereas 3-month mid-stromal densitometry correlated with ARTh and stiffness parameter at first applanation (SP-A1). By 12 months, total and mid/posterior densitometry had returned to or fallen below baseline, whereas anterior densitometry remained numerically above baseline. CDVA improved over follow-up, ECD remained stable, Kmax decreased modestly, and ARTh increased significantly. After accelerated epithelium-off CXL, corneal densitometry demonstrated layer- and time-dependent postoperative changes and showed time-specific associations with selected biomechanical parameters. Layer-specific densitometry may provide adjunctive information for evaluating early stromal remodeling after CXL.