Purpose:
To evaluate potential macular toxicity secondary to indocyanine green (ICG)-assisted internal limiting membrane (ILM) peeling during epiretinal membrane (ERM) surgery using spectral domain optical coherence tomography (SD-OCT).
Methods:
A retrospective review of 11 eyes of 11 patients that underwent combined ERM/ILM peeling using a 2.5 mg/mL dose of ICG dye (timed for one minute against the clock) for membrane visualization between July 2008 and April 2010, by a single surgeon (RDJ). Preoperative best corrected visual acuity (BCVA), central macular thickness (CMT) and SD-OCT (Spectralis®, Heidelberg Engineering) macular structural appearance were compared with the same parameters at postoperative months one, three and six.
Results:
Six of eleven patients were male. Mean patient age was 75.45 years. Mean preoperative logarithm of the minimum angle of resolution visual acuity (LogMAR VA) was 0.95 (20/200) with a range of 0.4 to 1.7 (20/50 to 20/1000). Mean postoperative LogMAR VA at 6 months was 1.32 (20/400) with a range of 0.4 to 2.6 (20/50 to 20/8000). With a p value of 0.16, there was no statistically significant relationship between pre- and post-operative BCVA. In addition, mean CMT on SD-OCT was 402.27 microns preoperatively and 354.0 microns at 6 months postoperatively, with a statistically insignificant p value of 0.21. However, and most notably, SD-OCT imaging revealed the presence of macular schisis as early as 1 month postoperative, and was present in each of 11 patient images. This finding could not be explained by any coexisting ocular comorbidities.
Conclusions:
ICG associated retinal toxicity is undoubtedly a controversial subject of several in vivo and in vitro studies. Our findings suggest that macular schisis may represent a previously unknown adverse effect of this dye. Further controlled studies are warranted to investigate the in vivo effect of ICG on retinal morphology and visual acuity.
Keywords: retina • vitreoretinal surgery