Corneal collagen cross-linking is a developing treatment that aims to strengthen the cornea, however, according to a 2015 Cochrane review, there is insufficient evidence to determine if it is useful in keratoconus. In 2016, however, the FDA approved cross-linking surgery as a treatment for keratoconus and recommended that a registry system should be set-up to evaluate the long-term treatment effect. The Save Sight Keratoconus Registry is an international database of keratoconus patients that is tracking outcomes of cross-linking in patients with keratoconus.