title: Corneal Biomechanical Response Following Collagen Cross-Linking With Rose Bengal-Green Light and Riboflavin-UVA.
abstract: OBJECTIVE
  To compare the biomechanical corneal response of two different corneal cross-linking (CXL) treatments, rose bengal-green light (RGX) and riboflavin-UVA (UVX), using noninvasive imaging.
  
  
  METHODS
  A total of 12 enucleated rabbit eyes were treated with RGX and 12 with UVX. Corneal dynamic deformation to an air puff was measured by high speed Scheimpflug imaging (Corvis ST) before and after treatment. The spatial and temporal deformation profiles were evaluated at constant intraocular pressure of 15 mm Hg, and several deformation parameters were estimated. The deformation profiles were modeled numerically using finite element analysis, and the hyperelastic corneal material parameters were obtained by inverse modeling technique.
  
  
  RESULTS
  The corneal deformation amplitude decreased significantly after both CXL methods. The material parameters obtained from inverse modeling were consistent with corneal stiffening after both RGX and UVX. Within the treated corneal volume, we found that the elasticity decreased by a factor of 11 after RGX and by a factor of 6.25 after UVX.
  
  
  CONCLUSIONS
  The deformation of UVX-treated corneas was smaller than the RGX-treated corneas. However, the reconstructed corneal mechanical parameters reveal that RGX produced in fact larger stiffening of the treated region (100-μm depth) than UVX (137-μm depth). Rose bengal-green light stiffens the cornea effectively, with shorter treatment times and shallower treated areas. Dynamic air puff deformation imaging coupled with mechanical simulations is a useful tool to characterize corneal biomechanical properties, assess different treatments, and possibly help optimize the treatment protocols.
authors.affiliation: Instituto de Optica Consejo Superior de Investigaciones Cientificas, Madrid, Spain.
authors.forename: Nandor
authors.initials: N
authors.lastname: Bekesi
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 / Q000627:therapeutic use*; D003315:Cornea / Q000187:drug effects / Q000503:physiopathology*; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D004548:Elasticity; D005456:Fluorescent Dyes / Q000627:therapeutic use; D007640:Keratoconus / Q000188:drug therapy* / Q000503:physiopathology; D017319:Photosensitizing Agents / Q000627:therapeutic use; D011817:Rabbits; D012256:Riboflavin / Q000627:therapeutic use*; D012395:Rose Bengal / Q000627:therapeutic use*; D014466:Ultraviolet Rays
chemical_list: D003432:Cross-Linking Reagents; D005456:Fluorescent Dyes; D017319:Photosensitizing Agents; D012395:Rose Bengal; D003094:Collagen; D012256:Riboflavin