title: The effects of indocyanine green and endoillumination on rabbit retina: an electroretinographic and histological study.
abstract: OBJECTIVE
  To evaluate the functional and morphological retinal toxicity associated with intravitreal injection of indocyanine green (ICG) dye in rabbit eyes during vitrectomy with endoillumination.
  
  
  METHODS
  20 eyes of 10 New Zealand pigmented rabbits were used in the study. All eyes underwent pars plana vitrectomy and removal of posterior vitreous cortex under endoillumination. In one eye of each rabbit, intravitreal injection of 0.1 ml of 2.5 mg/ml ICG was applied for 30 seconds followed by 10 minutes of endoillumination. The control eye had endoillumination only without ICG injection. Dark adapted and light adapted electroretinograms (ERGs) were performed before the surgery and 1 week after surgery for serial comparisons. Rabbits were killed 1 week after surgery and eyes were enucleated for histological examination.
  
  
  RESULTS
  Serial ERG comparisons showed significant reduction in the light adapted a-wave amplitude (p = 0.037) and significant delays in the dark adapted and light adapted b-wave latencies (p = 0.020 and p = 0.038, respectively) in the ICG treated eyes. Histological examinations demonstrated loss of photoreceptor outer segments with focal absence of photoreceptors in some areas in the ICG injected eyes.
  
  
  CONCLUSIONS
  Vitrectomy followed by intravitreal injection of 2.5 mg/ml ICG for 30 seconds with endoillumination may result in retinal toxicity causing functional and morphological retinal damages in rabbit eyes. The lowest concentration of ICG should be used if necessary for intraocular use to prevent potential retinal toxicity.
authors.affiliation: Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Eye Hospital, 147K Argyle Street, Kowloon, Hong Kong, People's Republic of China.
authors.forename: A K H
authors.initials: AK
authors.lastname: Kwok
authors.forename: T Y Y
authors.initials: TY
authors.lastname: Lai
authors.forename: C-K
authors.initials: CK
authors.lastname: Yeung
authors.forename: Y-S
authors.initials: YS
authors.lastname: Yeung
authors.forename: W W Y
authors.initials: WW
authors.lastname: Li
authors.forename: S W
authors.initials: SW
authors.lastname: Chiang
mesh_terms: D000818:Animals; D004396:Coloring Agents / Q000009:adverse effects*; D003623:Dark Adaptation / Q000502:physiology; D004596:Electroretinography / Q000379:methods; D007208:Indocyanine Green / Q000009:adverse effects*; D010786:Photoreceptor Cells / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D011817:Rabbits; D012160:Retina / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology; D014821:Vitrectomy / Q000379:methods*
chemical_list: D004396:Coloring Agents; D007208:Indocyanine Green