title: Safety testing of indocyanine green with different surgical light sources and the protective effect of optical filters.
abstract: OBJECTIVE
  The purpose of this study was to assess the light-induced cytotoxicity of indocyanine green (ICG) using different light sources commonly used in macular surgery and to assess the effect of optical filters.
  
  
  METHODS
  Primary cultures of porcine retinal pigment epithelium cells were incubated with 0.5 mg/mL ICG solution dissolved in 5% glucose and illuminated with a surgical light fiber for 3 or 15 minutes. Halogen, mercury vapor, xenon, and metal halide light sources were used. Cell viability was assessed using the MTT assay. Retinal pigment epithelium cells without illumination served as controls. The decomposition of ICG after illumination was analyzed by high-performance liquid chromatography.
  
  
  RESULTS
  Illumination of retinal pigment epithelium cells with all light sources with or without previous incubation with ICG did not affect cell viability compared with controls. Cell viability was significantly reduced when the cells were not rinsed immediately after incubation. The cytotoxic effect was abolished by a 475-nm long-pass filter. The high-performance liquid chromatography analysis of the illuminated ICG solution identified six cytotoxic ICG decomposition products.
  
  
  CONCLUSIONS
  Optical filters that narrow the emission spectrum of the light sources reduce the light-induced cytotoxicity of ICG. Optical filters applied in ICG-assisted macular surgery may reduce the risk of intraoperative cell damage.
authors.affiliation: Department of Ophthalmology, University Medical Center Schleswig-Holstein, Kiel, Germany. hillenka@hotmail.com
authors.forename: Jost
authors.initials: J
authors.lastname: Hillenkamp
authors.forename: Sofia
authors.initials: S
authors.lastname: Dydykina
authors.forename: Alexa
authors.initials: A
authors.lastname: Klettner
authors.forename: Felix
authors.initials: F
authors.lastname: Treumer
authors.forename: Rudolf
authors.initials: R
authors.lastname: Vasold
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Bäumler
authors.forename: Johann
authors.initials: J
authors.lastname: Roider
mesh_terms: D000818:Animals; D002470:Cell Survival; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D004396:Coloring Agents / Q000633:toxicity*; D005374:Filtration / Q000295:instrumentation*; D007208:Indocyanine Green / Q000633:toxicity*; D008027:Light; D055213:Retinal Pigment Epithelium / Q000187:drug effects* / Q000528:radiation effects*; D013552:Swine
chemical_list: D004396:Coloring Agents; D007208:Indocyanine Green