Corneal collagen crosslinking (CXL) has emerged as a frontline therapy in keratoconus and post-LASIK ectasia. This video lecture series explores the history and current uses of crosslinking, including epithelium-off, transepithelial, and concurrent crosslinking with corneal ring segments. In this segment, Dr. Theo Seiler reviews long-term safety outcomes and documented complications related to CXL for keratoconus, including failure rates, stromal scarring, and sterile infiltrates.