Reduction of ICG Toxicity on RPE With Whole Blood in ICG–assisted Macular Hole Surgery

Abstract

Abstract: : Purpose: To examine if whole blood could prevent the toxicity of indocyanine green (ICG) on retinal pigment epithelium (RPE) in vitro and prevent staining on RPE in ICG–assisted macular hole (MH) surgery. Methods: In the in vitro study, cultured human RPE cells were covered with balanced saline solution (BSS) or whole blood and then exposed to various concentration of ICG solution (from 0.05 to 5 mg/ml) diluted with BSS. The toxic effect of ICG in cultured human RPE cells was evaluated by mitochondrial dehydrogenase assay. In the clinical study, a prospective noncomparative review of a consecutive series of 20 patients (20 eyes) with MH from stage 3 to stage 4 who underwent MH surgery using ICG to stain internal limiting membrane (ILM) was performed. ICG solution (0.5 mg/ml) was used to stain ILM after heparinized autologous whole blood covered MH. Results: RPE cells were protected by whole blood which showed no decrease of mitochondrial dehydrogenase even in 5.0mg/ml concentration of ICG for 20 minutes. On the other hand, those exposed to ICG with BSS only demonstrated a decrease of mitochondrial dehydrogenase after incubation in 1.0 mg/ml for 20 minutes. Clinically, no postoperative staining on RPE and no atrophic RPE changes and other retinal changes were observed in the area of the previous MH area which was covered by heparinized autologous whole blood in all 20 eyes after follow–up for average 10.6 months (range 6–18 months). The hole was closed in 19 eyes (95%) in the first surgery and an improvement of visual acuity in 17 eyes (85%) in the most recent follow–up. Conclusions: In conclusion, heparinized whole blood could be used to prevent the toxic effect of ICG in PRE cell culture and prevent the staining of RPE in surgery of MH when ILM stained with ICG.

Keywords: macular holes • retinal pigment epithelium • vitreoretinal surgery