Pars Plana Vitrectomy with Internal Limiting Membrane Peeling for Refractory Diffuse Diabetic Macular Edema

PURPOSE To evaluate the effect of pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling for management of refractory diffuse diabetic macular edema (DME). METHODS In this prospective interventional case series, eyes with refractory diffuse DME unresponsive to macular photocoagulation and/or intravitreal bevacizumab, and best corrected visual acuity (BCVA) ≥ 20/200 and ≤ 20/60 underwent triamcinolone-assisted PPV with ILM peeling. Pre- and postoperative evaluations included a complete ophthalmologic examination, fluorescein angiography and optical coherence tomography (OCT). Main outcome measures were BCVA and central macular thickness (CMT). RESULTS Twelve eyes of 12 patients with mean age of 59.6±3.9 (range, 55-68) years were operated and followed for a mean period of 4.9±1.0 (range, 4-6) months. Mean BCVA at final examination was 0.82 ± 0.18 logMAR which was not significantly better than its preoperative value of 1.00 ± 0.80 logMAR (P=0.959). Visual acuity improved by at least 2 lines in 3 eyes (25%), remained stable in 7 eyes (58%) and decreased by at least 2 lines in 2 eyes (17%). Mean CMT at final examination was 315±95 μm, which was significantly less than its preoperative value of 467±107 μm (P=0.004). Complications included vitreous hemorrhage in 2 and cataract progression in 5 eyes. CONCLUSION PPV with ILM peeling for refractory diffuse DME seems to reduce macular thickness, but does not significantly improve visual acuity as observed after an intermediate-term follow up of about 6 months.