Persistent indocyanine green (ICG) fluorescence 6 weeks after intraocular ICG administration for macular hole surgery

Abstract.

Background: Macular hole surgery including vitrectomy and peeling of epiretinal membranes and the internal limiting membrane (ILM) has become a standard procedure in retinal surgery. Poor visualization of epiretinal membranes and the ILM is an obstacle to successful surgery. Recently, indocyanine green (ICG) has been reported to be a helpful intraocular substance in identifying these membranes. Methods: In a case of stage IV macular hole, epiretinal membranes and ILM were intraoperatively stained with three drops of 1:9 diluted ICG. After 1 min incubation the vitreous cavity was rinsed with Ringer's lactate solution, and the membranes were peeled. Autologous thrombocytes were applied to the macular hole, and the eye was endotamponaded with 20% SF6 gas. Six weeks postoperatively, visual acuity was measured and fundus photographs and autofluorescence images, as well as a multifocal ERG, were obtained. Results: Intraoperatively, the ILM could be nicely visualized by ICG, which allowed immediate peeling. Six weeks after surgery, the visual acuity had improved from 0.1 to 0.7 and the macular hole was closed. Autofluorescence imaging at 795 nm revealed a strong signal. Multifocal ERG recording showed regular amplitudes. Conclusion: ICG as an intraocular tool for staining of the ILM is helpful in macular hole surgery. We did not observe any negative effect on retinal function; however, we were surprised to identify traces of ICG in retinal fluorescein angiography images 6 weeks postoperatively.