Purpose: This study compares the efficacy and safety of conventional versus accelerated corneal collagen cross linking in treatment of progressive keratoconus.
Methods: This non-randomized interventional study was conducted on 79 eyes with keratoconus or corneal ectatic diseases. Patients' eyes were divided into two groups, group A (n=35 eyes) underwent conventional crosslinking (cCXL) and group B (n=44 eyes) underwent the accelerated (KXL) technique.
Results: No eyes lost any lines of visual acuity and more than 80% gained 1-4 lines in both UCVA and BCVA in both groups. Comparing both groups after 6 months, a more significant decrease in ECD was seen in the accelerated group at 6months (p=0.011), the mean cylindrical error showed a more significant improvement in the accelerated group (p=0.044), less reduction of pachymetry at thinnest location in KXL (P=0.008), but the mean depth of the demarcation line was significantly better and more homogenous in the conventional group (363.57±46.92µm) than the accelerated group (319.56±36.50µm) (P<0.001). Both groups showed insignificant change in the coefficient of variation for specular microscopy (P=0.574 and 0.528).
Conclusion: both types offer a significant improvement in UCVA and BCVA values, but cCXL offers a deeper demarcation line and less endothelial loss. KXL offers less reduction in pachymetry and better cylinder correction.