Densitometry Changes After Corneal Collagen Cross-Linking With Riboflavin and UVA Light in Patients With Keratoconus

Purpose: The aim of this study was to determine if quantitative changes in corneal densitometry, pachymetry, and age at the time of corneal cross-linking (CXL) correlate with CXL effectiveness. Methods: Electronic medical records of 148 eyes of patients who had CXL done at Vision NYC between 10/2016 and 03/2021 were analyzed. Data collected from preprocedure visit, 6 weeks, 3 months, 6 months, 12 months, and 18 months of follow-ups. A change in maximal keratometry from preprocedure visit to 18 months after CXL was used as a measure of CXL effectiveness. Age, preprocedure pachymetry, change in densitometry, and pachymetry from preprocedure values at each visit were checked for correlation with CXL effectiveness. Results: Age of CXL did not correlate with CXL effectiveness. There was a statistically significant negative correlation between initial pachymetry and final change in keratometry. We found a moderate positive correlation of densitometry change in superficial central and paracentral zones at 6 months, 12 months, and 18 months with CXL effectiveness. Change in densitometry in central central zone at 3 and 6 months and posterior central and paracentral zones at 3 months also positively correlated with CXL effectiveness. Conclusions: Our study demonstrates the natural history of densitometry, pachymetry, and keratometry values in patients with keratoconus after CXL. We also demonstrated a correlation between change in densitometry and CXL effectiveness with stronger correlation in more central and superficial corneal zones. Our data suggest that CXL may lead to a greater flattening of the cornea in patients with more advanced keratoconus.