Prior to the advent of the corneal collagen cross-linking procedure, no conservative treatment for corneal ectasia existed, with 20% of keratoconus patients progressing to eventually require penetrating keratoplasty. Collagen cross-linking in the cornea as a treatment for ectasia was the breakthrough of Theo Seiler, MD, PhD, a professor of ophthalmology at Dresden Technical University, Germany at the time of the discovery. As he has told the story many times, Professor Seiler had his moment of inspiration in a dental chair, when he learned that UV light is used to harden dental fllings through the induction of cross-links. If the natural increase in non-enzymatic cross-linking that occurred with age led to increased corneal strength, could a physical means of inducing cross-linking be used to stabilize keratoconus? This initiated his frst investigation to determine “whether the elastic modulus of corneal tissue can be increased by cross-links of collagen fbrils induces by UV irradiation of the cornea” . Cross-linking was developed as a method of stabilizing the structurally weak corneas of patients with keratoconus, and has not only revolutionized the treatment of ectatic disorders, but has also become a platform technology including accelerated crosslinking (ACXL) with numerous additional clinical applications.