Corneal Densitometry Changes after Epithelium-Off Corneal Collagen Crosslinking

Background Keratoconus is a progressive non-inflammatory, degenerative disease that affects the integrity of the collagen matrix within the corneal stroma. Corneal cross-linking (CXL) has been described as the only modality in halting the disease progression over the past decade. Aim of the Work To compare the change in corneal densitometry before and 6 months after CXL using our unique protocol. Patients and Methods A prospective observational study was conducted on 30 eyes of 30 patients with progressive keratoconus. Epitheliumoff CXL was done with application of Riboflavin (VibeX RapidTM) for 6 minutes at a rate of 1 drop/ minute. UVA was delivered using the Avedro KXL machine (Avedro, Waltham, MA, USA) using the following parameters: 7.2 joules, 12 milli watt/ minute and 10 minutes of accelerated continuous UV delivery. Results Within the anterior (120 um) stromal layer, the concentric zones (0 to 2 mm) and (2 to 6 mm) showed a significant elevation of mean densitometry 6 months post-surgery (P = 0.020) and (P = 0.023) respectively compared to the baseline, However the concentric zones (6 to 10 mm) and (10 to 12 mm) showed a non-significant elevation of mean densitometry 6 months post-surgery (P = 0.167) and (P = 0.234) respectively compared to the baseline. Conclusion There is a significant increase in corneal densitometry 6 months postsurgery of the anterior stromal layer within the central 6 mm zone.