The effects of collagen cross-linking on corneal density: a comparison between accelerated and conventional methods

Purpose: To compare the corneal density before and after accelerated versus conventional corneal cross-linking (CXL). Methods: Pentacam densitometry and corneal mapping were performed before and 6 months following the randomly assigned intervention. Corneal density was measured over different zones and layers of the cornea by two independent ophthalmologists. Total corneal density was calculated. The patients were followed up for the occurrence of procedure-related and unrelated complication 1 week, 1 month and a final visit around 6 months (180 ± 10 days) after the procedure, during which the corneal density was remeasured and recorded. Results: Twenty-three patients were enrolled. There was a significant increase in corneal density over the anterior layer (P < 0.001) and middle corneal layer (P = 0.035). Additionally, the corneal density significantly increased in 0–2 and 2–6 mm zones (P < 0.001), as well as total density (P = 0.002) following corneal CXL. Although there was no significant difference in the corneal density between the two CXL groups, the increase in corneal density was only significant in group A for the 6–10 mm zone and the posterior corneal layer. Conclusion: Both the conventional and accelerated CXL methods increase the overall corneal density with exception of posterior central corneal layer and the 6–10 mm zone, which is only increased in the accelerated method.