The effect of indocyanine-green on functional outcome of macular pucker surgery

Abstract

PurposeTo compare functional results after surgery for macular pucker either with or without indocyanine-green staining of the internal limiting membrane (ILM) and to evaluate the ultrastructure of the tissue removed. DesignRetrospective analysis of two successive, consecutive, interventional case series. MethodsFunctional outcome (visual acuity, Goldmann perimetry) of 48 eyes of 48 consecutive patients with (group 1, n = 20) or without (group 2, n = 28) intraoperative use of indocyanine-green (ICG) was retrospectively analyzed. For statistical analysis, best-corrected visual acuity measured at the last presentation was considered. Only patients with an idiopathic macular pucker were included. Surgery consisted of three-port pars plana vitrectomy, and removal of epiretinal tissue and the ILM in a second step. Commercially available ICG with a concentration of .05% and an osmolarity of 275 mOsm was used to stain the ILM. The surgical technique used for both groups was identical, except the use of ICG. Epiretinal tissue of all eyes was harvested and prepared for ultrastructural analysis using light and electron microscopy. ResultsFollow-up time was 8.5 months in group 1 and 5.4 months in group 2. Whereas patients operated on without ICG experienced a significant improvement of median best-corrected visual acuity from 20/63 (range, 20/400 to 20/32) preoperatively to 20/40 (range, 20/200 to 20/25) postoperatively (P < .001), median best-corrected visual acuity remained 20/63 before (range, 20/200 to 20/63) and after (range, 20/400 to 20/20) (P > .9) ICG-assisted peeling. There was a statistically significant difference (P = .013) in best-corrected postoperative visual acuity of patients with and without the use of ICG. An improvement of vision was noted in 86% of patients without and 55% of patients with ICG-assisted surgery. Thirty-five percent of patients after ICG application presented with a deterioration of visual acuity. Furthermore, we observed large visual field defects in 7 of 20 patients after ILM staining. No visual field defects were noted after conventional peeling. Histologic analysis revealed clear differences between the two groups concerning the amount of cellular elements adjacent to the retinal surface of the ILM: There was more cellular debris visible in specimens after ICG application during surgery. Additionally, in contrast to surgery without ILM staining, epiretinal cells had ruptured and lost their cellular integrity after ICG-assisted vitrectomy. ConclusionsIndocyanine green-assisted surgery for macular pucker might have an adverse effect on functional outcome. Although there were obvious differences in the ultrastructure of tissue removed during surgery, our observations cannot be explained by histologic analysis alone. Other, so far unknown mechanisms of action must be considered.