Morphologic and clinical effects of subretinal injection of indocyanine green and infracyanine green in rabbits

Purpose: the aim of this study was to determine the effects of subretinal injection of indocyanine green (ICG), infracyanine (IfCG), and balanced salt solution (BSS) in rabbits.Methods: Ten (10) animals were subjected to a subretinal injection of 0.05% ICG (279 mOsm), 0.5% IfCG (276 mOsm), and BSS (300 mOsm) used as a control. Animals were examined at 6, 12, and 24 h and 14 days following the surgical procedure by indirect binocular ophthalmoscopy, fluorescein angiography (FA), and light and transmission electron microscopy.Results: the subretinal injection of ICG caused damage to all retinal layers and retinal pigment epithelium (RPE) during the entire follow-up. Subretinal injection of IfCG resulted in abnormalities of the photoreceptor outer segments (POSs) during the entire follow-up; however, abnormalities of the photoreceptor inner segments (PISs) and outer nuclear layer (ONL) were observed only 24 h and 14 days after surgery; no RPE damage was observed. FA showed that window defects were more prominent in the subretinal ICG bleb position than the IfCG-related area. BSS caused only abnormalities of the POS layer and no RPE alterations.Conclusions: Subretinal injection of 0.05% ICG results in more significant retinal damage than 0.5% IfCG. in this model, iodine-free IfCG demonstrates a safer profile than a tenfold lower concentration of ICG, which contains iodine in its composition.Hosp Reg San Jose, Dept Ophthalmol, BR-88015300 Florianopolis, SC, BrazilUniversidade Federal de São Paulo, Vis Inst IPEPO, Dept Ophthalmol, São Paulo, BrazilUniversidade Federal de São Paulo, Ctr Electron Microscopy CEME, São Paulo, BrazilCtr Paradis Monticelli, Marseille, FranceUniversidade Federal de São Paulo, Vis Inst IPEPO, Dept Ophthalmol, São Paulo, BrazilUniversidade Federal de São Paulo, Ctr Electron Microscopy CEME, São Paulo, BrazilWeb of Scienc