Morphological and functional damage of the retina caused by intravitreous indocyanine green in rat eyes

Hiroshi Enaida, Taiji Sakamoto, Toshio Hisatomi, Yoshinobu Goto, Tatsuro Ishibashi

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215 Citations (Scopus)


Background: This study was designed Ito investigate the influence of intravitreal indocyanine green (ICG) on retinal morphology and function. Methods: Brown Norway rats eyes (n=24) were vitrectomized by the injection of 0.05 ml of 100% SF6 gas. Two weeks later, ICG solution was injected into the vitreous cavity of vitrectomized eyes at a dose of 25 mg/ml, 2.5 mg/ml, 0.25 mg/ml or 0.025 mg/ml (0.05 ml/eye). Retinal toxicity was histologically assessed by light microscopy on day 10. The retinal function was also evaluated by electroretinography (ERG) in the low-dose groups (0.25 mg/ml and 0.025 mg/ml) after 10 days and again after 2 months,. Sham-operated eyes (SF6 injected followed by 0.05 ml of BSS plus, n=6) were used as controls. Results: In the high-dose group (25 mg/ml ICG), the retinal structure was severely deformed and the retinal pigment epithelium partly disappeared. In eyes with 2.5 mg/ml ICG, the retinal structure was also affect-ed but less strongly so than with 25 mg/ml. No apparent pathologic change was observed in the low-dose groups (0.25 mg/ml or 0.025 mg/ml) by light microscopy. In contrast, 10 days later the amplitude of dark-adapted a- and b-waves of ERGs in the eyes of low-dose group rats were found to have decreased. In addition the light-adapted b-waves did not change significantly. These changes remained for 2 months. Conclusion: Even at a low dose (0.025 mg/ml), intravitreous ICG induced functional damage of the retina without any apparent morphological damage. This information should be taken into account when clinically administering ICG into the vitreous cavity.

Original languageEnglish
Pages (from-to)209-213
Number of pages5
JournalGraefe's Archive for Clinical and Experimental Ophthalmology
Issue number3
Publication statusPublished - 2002

All Science Journal Classification (ASJC) codes

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience


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