Abstract
Purpose: Evaluating the impact of pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling and intravitreal bevacizumab (IVB) injection to manage refractory diffuse diabetic macular edema (DME).Methods: In the current prospective interventional clinical study, eyes with refractory diffuse DME with no response to a minimum of three times IVB injections, and best corrected visual acuity (BCVA) of equal or more than 20/200 and equal or lower than 20/60 were subjected to PPV with ILM peeling and intravitreal avastin injection. Pre- and post-operative assessments were a comprehensive ophthalmologic evaluation, fluorescein angiography, and optical coherence tomography (OCT). BCVA, central macular thickness (CMT) and contrast sensitivity (CS) were major outcomes. Results: Fifteen eyes of 13 cases (mean age: 63±5.19 (range, 54-70) years) were subjected to operation and a follow-up of 3 months. Average BCVA at last test was 0.74 ± 0.19 LogMAR that showed no improvement compared with its value before intervention (0.84 ± 0.14 LogMAR) (P=0.073). Average CMT at last test was 328.26±129 µm that was significantly lower compared with its value before operation (450.8±114 µm) (P=0.002) and a significant improvement in CS was found (from 16.66 ± 8.99 mm to 18.13 ±1.22mm;p=0.003). CMT and BCVA (correlation coefficient =0.419,p=0.120), BCVA and CS (correlation coefficient =-0.336,p=0.221) , and CS and CMT (correlation coefficient =-0.07,p=0.979) were found with no significant correlation. Conclusion: PPV with ILM peeling and IVB regarding refractory diffuse DME reduced macular width along with CS improvement, but does not significantly improve visual acuity.