Sistema FMUSP-HC: Faculdade de Medicina da Universidade de São Paulo (FMUSP) e Hospital das Clínicas da FMUSPCRESTA, F. B.SIMONCELLI, R.LUCAS, M. B.2023-12-042023-12-042022Cresta, F. B.; Simoncelli, R.; Lucas, M. B.. Corneal Collagen Cross-Linking Controversies. In: . Keratoconus: A Comprehensive Guide to Diagnosis and Treatment: SPRINGER INTERNATIONAL PUBLISHING, 2022. p.393-401.978-303085361-7; 978-303085360-0https://observatorio.fm.usp.br/handle/OPI/57271Corneal collagen cross-linking (CXL) has been shown to be a safe and effective surgery to halt the progression of keratoconus. Keratoconus (KC) is a bilateral, asymmetric, noninflammatory, and progressive corneal ectasia. It results in corneal thinning and protrusion leading to myopia and irregular astigmatism. In the past, corneal transplantation was the only surgical option for visual recovery of advanced cases. The conventional or Dresden corneal collagen cross-linking protocol (C-CXL) includes removal of the central corneal epithelium (8–9 mm diameter) followed by soaking the stroma with the photosensitizer riboflavin (vitamin B2). After 30 min of soaking, the stroma is irradiated with ultraviolet-A during 30 minutes (3mW/cm2; total energy 5.4 J/cm2). This leads to the formation of reactive oxygen species (ROS) and a photochemical reaction that induces collagen covalent bonds, with consequent stiffening and strengthening of the cornea. Conventional protocol (C-CXL) is time-consuming and can lead to complications due to the removal of the epithelium. Since the first publication in 2003, corneal collagen cross-linking has evolved with new treatment options. Cross-linking in pediatric patients, the use of oral riboflavin, and transepithelial, accelerate, and pulsed protocols are still controversial about its safety and effectiveness. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2022.engrestrictedAccessCorneal cross-linkingEpithelium-offIontophoresisKeratoconusPediatricbookPartCopyright SPRINGER INTERNATIONAL PUBLISHING10.1007/978-3-030-85361-7_32