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

Background: Macular hole surgery including vitrectomy and peeling of epiret inal membranes and the internal limiting membrane (ILM) has become a standa rd procedure in retinal surgery. Poor visualization of epiretinal membranes and the ILM is an obstacle to successful surgery. Recently, indocyanine gr een (ICG) has been reported to be a helpful intraocular substance in identi fying these membranes. Methods: In a case of stage IV macular hole, epireti nal membranes and ILM were intraoperatively stained with three drops of 1:9 diluted ICG. After 1 min incubation the vitreous cavity was rinsed with Ri nger's lactate solution, and the membranes were peeled. Autologous thromboc ytes were applied to the macular hole, and the eye was endotamponaded with 20% SF6 gas. Six weeks postoperatively, visual acuity was measured and fund us photographs and autofluorescence images, as well as a multifocal ERG, we re obtained. Results: Intraoperatively, the ILM could be nicely visualized by ICG, which allowed immediate peeling. Six weeks after surgery, the visua l acuity had improved from 0.1 to 0.7 and the macular hole was closed. Auto fluorescence imaging at 795 nm revealed a strong signal. Multifocal ERG rec ording showed regular amplitudes. Conclusion: ICG as an intraocular tool fo r staining of the ILM is helpful in macular hole surgery. We did not observ e any negative effect on retinal function; however, we were surprised to id entify traces of ICG in retinal fluorescein angiography images 6 weeks post operatively.