In the U.S., CXL and topography-guided laser ablation were approved independently, but not together. Another variation in technique involves the use of mitomycin-C (MMC), which is effective in reducing corneal haze after the laser surface ablation. Use of MMC during the laser custom CXL was associated with better outcomes, but in separate trials that could not be directly compared. This study will use OCT measurements to evaluate the magnitudes of direct and indirect laser actions after the procedure.