Purpose: To evaluate the effect of indocyanine green (ICG) diluted with glucose 5% on the human retina in an experimental setting in postmortem eyes and during surgery for macular hole formation.
Design: Histopathological evaluation.
Methods: Possible adverse effects of two different solutions of 0.05% ICG (Pulsion, Munich, Germany; and Infracyanine, Laboratoire SERB, Paris, France) diluted with glucose 5% were evaluated in four eyes of two donors. In one eye of each donor, the ICG-stained macula was illuminated with 380 to 760 nm using the light source of a commonly used vitrectomy machine. In the other eye, ICG was applied to the macula without illumination. The retinal specimens were evaluated using light- and electron microscopy. Additionally, the ultrastructure of the internal limiting membrane (ILM) of four eyes that underwent ICG-assisted vitrectomy for macular hole formation was examined.
Results: In the postmortem study, both solutions of ICG caused significant morphologic alterations of the inner retina after light exposure. There was disorganization of the inner retina and complete loss of ILM after application of the dye and illumination. In contrast, no abnormalities were found after application of the dye without illumination and in unstained control specimens. No differences were noted between the two ICG products. Specimens of the ILM harvested during vitrectomy revealed cellular elements adjacent to the retinal side of the ILM.
Conclusions: Staining of the ILM using ICG diluted in glucose 5% followed by illumination might induce an adverse effect on the inner retina and may result in an alteration of the cleavage plane from the ILM to the innermost retinal layers.