Rationale A Riboflavin solution is administered to the cornea in the form of eye drops to the patient. After an administration of 25 minutes (one drop every 2 minutes), the cornea is then irradiated with UV-A light at a wavelength of 365nm and a total energy of 5.4 J/cm2 (use 30 min @ 3 mW/cm2, 10 min @ 9 mw/cm2, or 5 min @ 18mW/cm2). These settings are identical with the standard CXL settings routinely used in clinical practice worldwide. The safety of these settings has been verified in multiple experimental and clinical studies over the past 15 years.