title: Biomechanical Changes After In Vivo Collagen Cross-Linking With Rose Bengal-Green Light and Riboflavin-UVA.
abstract: To compare corneal biomechanical properties after in vivo and ex vivo cross-linking (CXL) using rose bengal-green light (RGX) or riboflavin-UVA (UVX).
  
  
  
  Corneas of 30 rabbits were treated in vivo by the two CXL modalities monolaterally (Group 1) or bilaterally (Group 2). Rabbits in Group 1 were euthanized 1 month after treatments and in Group 2 two months after treatment. Ex vivo CXL was also performed. Eyes were measured by Scheimpflug air puff corneal deformation imaging (Corvis ST) under constant IOP. Corneal deformation parameters were assessed. Inherent corneal biomechanical properties were estimated using inverse finite element modeling.
  
  
  
  Peak to peak distance decreased 16% 2 months after RGX, and 4% and 20% 1 and 2 months after UVX, respectively. The equivalent Young's modulus (Eeq) increased relative to the control during the post treatment period for both RGX and UVX. The Eeq increased by factors of 3.4 (RGX) and 1.7 (UVX) 1 month and by factors of 10.7 (RGX) and 7.3 (UVX) 2 months after treatment. However, the Eeq values for ex vivo CXL were much greater than produced in vivo. The ex vivo Eeq was greater than the 1-month in vivo values by factors of 8.1 (RGX) and 9.1 (UVX) and compared with 2 month by factors of 2.5 (RGX) and 2.1 (UVX).
  
  
  
  These results indicate that corneal stiffness increases after CXL, and further increases as a function of time after both RGX and UVX. Also, while biomechanical properties determined after ex vivo CXL are indicative of corneal stiffening, they may not provide entirely accurate information about the responses to CXL in vivo.
authors.affiliation: Instituto de Optica, Consejo Superior de Investigaciones Cientificas, Madrid, Spain.
authors.forename: Nandor
authors.initials: N
authors.lastname: Bekesi
authors.affiliation: Departamento de Biología Celular, Histología y Farmacología, GIR de Técnicas Ópticas para el Diagnóstico, Universidad de Valladolid, Valladolid, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Gallego-Muñoz
authors.affiliation: Departamento de Biología Celular, Histología y Farmacología, GIR de Técnicas Ópticas para el Diagnóstico, Universidad de Valladolid, Valladolid, Spain.
authors.forename: Lucía
authors.initials: L
authors.lastname: Ibarés-Frías
authors.affiliation: Instituto de Optica, Consejo Superior de Investigaciones Cientificas, Madrid, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Perez-Merino
authors.affiliation: Departamento de Biología Celular, Histología y Farmacología, GIR de Técnicas Ópticas para el Diagnóstico, Universidad de Valladolid, Valladolid, Spain.
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Martinez-Garcia
authors.affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States.
authors.forename: Irene E
authors.initials: IE
authors.lastname: Kochevar
authors.affiliation: Instituto de Optica, Consejo Superior de Investigaciones Cientificas, Madrid, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: Marcos
mesh_terms: D000818:Animals; D003094:Collagen / Q000494:pharmacology*; D003316:Corneal Diseases / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D003319:Corneal Stroma / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology*; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D004195:Disease Models, Animal; D004548:Elasticity; D005456:Fluorescent Dyes / Q000494:pharmacology; D017319:Photosensitizing Agents / Q000494:pharmacology; D011817:Rabbits; D012256:Riboflavin / Q000494:pharmacology*; D012395:Rose Bengal / Q000494:pharmacology*; D014466:Ultraviolet Rays
chemical_list: D003432:Cross-Linking Reagents; D005456:Fluorescent Dyes; D017319:Photosensitizing Agents; D012395:Rose Bengal; D003094:Collagen; D012256:Riboflavin