Scheimpflug Corneal Densitometry analysis after accelerated cross-linking in pediatric and adult Keratoconus patients

Abstract

Purpose: To compare the corneal densitometry in patients under and above 18 years of age who have had corneal collagen cross-linking (CXL) treatment for keratoconus. Method: Seventy-four eyes of 55 patients who have had corneal CXL with a diagnosis of keratoconus were included. Patients under 18 years were included in group 1, while patients over 18 years of age were in group 2. Corneal thickness and corneal densitometry were measured and recorded with Pentacam Scheimpflug imaging system, before and after corneal CXL. Corneal thicknesses of patients were also measured by ultrasonic pachymetry and compared with Scheimpflug system measurements, after CXL. Results: Corneal densitometry value before CXL was 19.84±2.67 GSU in group 1, while 21.54±3.32 GSU after the procedure and the difference was statistically significant (p=0.048). Similarly, corneal densitometry value in group 2 was 18.74±1.56 GSU before CXL, while 24.53±10.46 GSU after the procedure and the difference was significant (p<0.0001). Corneal thickness measured before CXL with the Scheimpflug imaging system was 473.04±24.23 µ in group 1 and 467.89±29.09 µ in group 2. Corneal thickness after CXL were 461.88±27.64 µ and 446.42±32.76 µ in group 1 and group 2, respectively, and the difference was statistically significant (p=0.003, p<0.0001, respectively). Conclusion: Corneal haze occures in children and adults after CXL in keratoconus. More haze occurs in adults than children. Corneal densitometry provides objective data in haze. Ultrasonic pachymetry can provide more accurate measurements than Scheimpflug camera in thickness measurements of corneas with haze.