title: Effect of indocyanine green intraocular stain on human and rabbit corneal endothelial structure and viability. An in vitro study.
abstract: OBJECTIVE
  To evaluate the direct effect of intraocular indocyanine green (ICG) on endothelial cell function, ultrastructure, and viability in human and rabbit corneas.
  
  
  METHODS
  A laboratory evaluation study.
  
  
  METHODS
  Paired human and rabbit corneas were mounted in an in vitro specular microscope for endothelial cell perfusion. One corneal endothelium was perfused with 25 mg ICG dissolved in 0.5 mL aqueous solvent in 4.5 mL balanced salt solution (BSS(R)) for 3 minutes followed by washout with a control solution. The percentage of ICG exposed to the corneal endothelium was 0.5%. The paired cornea was perfused with the same solution without ICG, followed by the washout. The corneas were fixed for scanning and transmission electron microscopy (TEM). In another group, the endothelial viability was determined using a live cell/dead cell assay.
  
  
  RESULTS
  In rabbit corneas, the mean corneal swelling rate was 12.9 microm/h +/- 1.2 (SEM) in the ICG corneas and 2.8 +/- 1.9 microm/h in the controls. Scanning electron microscopy and TEM revealed a normal endothelial cell mosaic. The control electron micrographs were similar. In human corneas, the mean swelling rate was 19.1 +/- 2.8 microm/h in the ICG corneas and 19.2 +/- 2.6 microm/h in the controls. Scanning electron microscopy and TEM revealed intact junctions with slight cellular vacuolization, similar to that in the controls. In the live cell/dead cell subgroup, the mean damage was 17.3% +/- 1.7% in the ICG-exposed corneas and 22.0% +/- 8.9% in the controls.
  
  
  CONCLUSIONS
  Three-minute exposure to ICG in BSS had no adverse effect on corneal endothelial function, ultrastructure, or viability in human and rabbit corneas. This study provides a safety profile for the corneal endothelium when ICG is used as an intraocular tissue stain in ophthalmic surgery.
authors.affiliation: Emory Eye Center, Emory University, Atlanta, Georgia 30322, USA.
authors.forename: Glenn P
authors.initials: GP
authors.lastname: Holley
authors.forename: Abu
authors.initials: A
authors.lastname: Alam
authors.forename: Aantariksha
authors.initials: A
authors.lastname: Kiri
authors.forename: Henry F
authors.initials: HF
authors.lastname: Edelhauser
mesh_terms: D000818:Animals; D002452:Cell Count; D002470:Cell Survival / Q000187:drug effects*; D004396:Coloring Agents / Q000494:pharmacology*; D004728:Endothelium, Corneal / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure*; D006801:Humans; D007208:Indocyanine Green / Q000494:pharmacology*; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D011817:Rabbits; D012449:Safety; D013997:Time Factors
chemical_list: D004396:Coloring Agents; D007208:Indocyanine Green