Abstract
Abstract: :
Purpose: This study was designed to investigate the influence of intravitreal indocyanine green (ICG) on the 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 and 0.025 mg/ml (0.05 ml/each eye). Retinal toxicity was histologically assessed by light microscopy on Day 10. The retinal function was also evaluated by electroretinogram (ERG) in low dose groups (0.25 mg/ml or 0.025 mg/ml) after both 10 days and 2 months. Results: In the high dose group (25 mg/ml ICG), the retinal structure was strongly deformed while the retinal pigment epithelium partly disappeared. In eyes with 2.5 mg/ml ICG, the retinal structure was also destructive but less prominent than those 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 of low dose group rats were found to have decreased. In addition the light-adapted b waves did not change significantly. These changes also remained for 2 months. Conclusion: Even with a low dose of intravitreous ICG (0.025 mg/ml), ICG induced functional damage on the retina without any apparent morphological damage. This information should therefore be carefully taken into account when clinically administering ICG into the vitreous cavity.
Keywords: 390 drug toxicity/drug effects • 396 electroretinography: non-clinical • 567 retinal pigment epithelium