title: Corneal light backscattering after transepithelial corneal crosslinking using iontophoresis in donor human corneal tissue.
abstract: OBJECTIVE
  To analyze the spatial distribution and time course of corneal light backscattering before and after transepithelial corneal crosslinking using iontophoresis.
  
  
  METHODS
  Fondazione G.B. Bietti-IRCCS, Rome, Italy.
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  Three donor human eyes with an intact corneal epithelium had transepithelial iontophoresis corneal crosslinking (using rapid ultraviolet-A [UVA] irradiation), and 3 donor eyes without corneal epithelium had standard corneal crosslinking (using standard UVA irradiation). In addition, 3 donor eyes had iontophoresis and rapid corneal crosslinking after corneal deepithelialization (epi-off iontophoresis corneal crosslinking). Scheimpflug images (Pentacam HR) of each eye globe were acquired before and immediately after administration of riboflavin 0.1% solutions and 5, 10, 30, and 120 minutes after the corneal crosslinking procedures. Corneal light backscattering was quantified across the anterior 280 μm thickness at several points from the optical center to 3.0 mm from the center.
  
  
  RESULTS
  Light backscattering significantly increased after iontophoresis (P < .001) in specimens with and without intact epithelium. It decreased significantly after transepithelial iontophoresis corneal crosslinking and epi-off iontophoresis corneal crosslinking (P < .001), approaching the baseline values. After standard stromal soaking with riboflavin, a large increase in corneal light backscattering was found compared with baseline measurements (P < .001) that remained unchanged up to 30 minutes after standard corneal crosslinking (P = .92). The light backscattering increase after iontophoresis in corneas with epithelium was lower than after standard soaking (P = .01). No differences were found between specimens without epithelium after iontophoresis and standard stromal soaking (P = .06).
  
  
  CONCLUSIONS
  Scheimpflug photography provided an indirect biomarker of stromal permeation of riboflavin. Iontophoresis efficiently delivered riboflavin through the epithelium.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors: From the G.B. Bietti Foundation-IRCCS (M. Lombardo, Serrao) and Vision Engineering Italy srl (G. Lombardo), Rome, and the CNR-IPCF Unit of Support of Cosenza (Carbone, G. Lombardo), Rende, Italy. Electronic address: mlombardo@visioeng.it.
authors: Marco
authors: M
authors: Lombardo
authors: From the G.B. Bietti Foundation-IRCCS (M. Lombardo, Serrao) and Vision Engineering Italy srl (G. Lombardo), Rome, and the CNR-IPCF Unit of Support of Cosenza (Carbone, G. Lombardo), Rende, Italy.
authors: Sebastiano
authors: S
authors: Serrao
authors: From the G.B. Bietti Foundation-IRCCS (M. Lombardo, Serrao) and Vision Engineering Italy srl (G. Lombardo), Rome, and the CNR-IPCF Unit of Support of Cosenza (Carbone, G. Lombardo), Rende, Italy.
authors: Giovanni
authors: G
authors: Carbone
authors: From the G.B. Bietti Foundation-IRCCS (M. Lombardo, Serrao) and Vision Engineering Italy srl (G. Lombardo), Rome, and the CNR-IPCF Unit of Support of Cosenza (Carbone, G. Lombardo), Rende, Italy.
authors: Giuseppe
authors: G
authors: Lombardo
mesh_terms: D003094:Collagen / Q000378:metabolism; D003315:Cornea / Q000187:drug effects*; D003319:Corneal Stroma / Q000378:metabolism; D003432:Cross-Linking Reagents; D019573:Epithelium, Corneal / Q000187:drug effects; D019466:Glare; D006801:Humans; D007478:Iontophoresis / Q000379:methods*; D008027:Light; D017319:Photosensitizing Agents / Q000494:pharmacology*; D012256:Riboflavin / Q000494:pharmacology; D012542:Scattering, Radiation; D014019:Tissue Donors; D014466:Ultraviolet Rays
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin