Comparative Analysis of Corneal Densitometry Changes Following Standard Versus Accelerated Corneal Cross-Linking Protocol.

Background and Objectives: The aim of this study is to evaluate and compare changes in corneal densitometry after standard (30 min exposure time of 3 mW/cm2 UVA) and accelerated (10 min exposure time of 9 mW/cm2 UVA) protocols of corneal cross-linking (CXL) in patients with progressive keratoconus. Materials and Methods: This study included a total of 38 eyes of 38 patients divided into two equal-sized subgroups. CXL was performed in one group according to the standard epithelium-off protocol (30 min, 3 mW/cm2 UVA) and in the other group according to an accelerated epithelium-off protocol (10 min, 9 mW/cm2 UVA). Scheimpflug imaging was used to evaluate corneal densitometry in the anterior, central, and posterior corneal layers in three concentric zones (0-2 mm, 2-6 mm, and 6-10 mm) at baseline and 1, 3, and 9 months after surgery. Results: This study included 38 patients divided into two subgroups of 19. One group of patients underwent standard and the other accelerated CXL protocol. Participants in the accelerated group were significantly older (p < 0.001). 9 months after CXL treatment, the accelerated group showed higher central and posterior corneal densitometry values, but, after adjusting for age and baseline values, ANCOVA analysis revealed no significant intergroup differences. Both protocols led to overall reductions in corneal densitometry over time. Conclusions: Both the standard and accelerated CXL protocols induce transient corneal haze, which can be objectified by increased corneal densitometry values in first three months post-CXL. The dynamics of the onset and recovery of postoperative corneal haze are comparable and similar in both protocols.