Ist die Entfernung der Membrana limitans interna (ILM) immer erforderlich bei Patienten mit dem therapierefraktären diffusen diabetischen Makulaödem ohne Nachweis von epimakulären Proliferationen

Purpose: The aim of this study was to evaluate the effect of the internal limiting membrane (ILM) peeling in eyes with diabetic macular edema (DME) but without evident epimacular proliferation or cellophane maculopathy that were unresponsive to laser photocoagulation. Secondly we wanted to determine whether ILM peeling is always essential in DME surgery and whether it improves the functional outcome. Patients and Methods: In a prospective controlled study, ten patients with similar degrees and duration of DME in both eyes were followed-up for more than 6 months after bilateral vitrectomy with and without ILM peeling. Trypan blue 0.2% was used to stain the ILM during surgery. We evaluated the anatomic outcome as detected by bimicroscopic evaluation and optical coherence tomography (OCT) and the visual outcome. Intraoperatively and postoperatively any complications occurring were documented. Results: Baseline BCVA and foveal thickness ranged, respectively, from 20/50 to 20/400 (mean 20/110) and 430 to 840pm (mean 618) in eyes that underwent ILM peeling, 20/40 to 20/400 (mean 20/120) and 390 to 910 μm (mean 623 μm) in eyes without ILM peeling. There were no significant differences between the both groups in baseline BCVA (P = 0.4691, Wilcoxon rank sum test) or foveal thickness (P = 0.8204, Wilcoxon rank sum test). At six-months follow-up, mean BCVA improved significantly in both groups, from 20/110 to 20/60 (P= 0.0427, Wilcoxon signed rank test) in eyes that underwent ILM peeling and from 20/120 to 20/80 (P = 0.0482, Wilcoxon signed rank test) in eyes without ILM peeling. Mean foveal thickness decreased significantly from 618 to 265 (P = 0.0050) in eyes with ILM peeling and from 623 to 311 (P = 0.0050) in eyes without ILM peeling. Visual acuity improved by two or more lines in five eyes (50%) of each group. There were no significant differences in the improvement of BCVA and decreasing of foveal thickness between the both groups (Wilcoxon rank sum test, P = 0.9083, P = 0.2720, respectively). Cyst rupture with formation of macular hole was documented in one eye after ILM peeling. Conclusions: Vitrectomy with or without ILM peeling may improve BCVA and decrease foveal thickness. ILM peeling was not found to enhance the improvement of VA postoperatively. A larger study is required to determine whether ILM peeling is essential in surgery for DME without epimacular proliferation or cellophane maculopathy.