Combined vitrectomy and intravitreal injection versus combined laser and injection for treatment of intractable diffuse diabetic macular edema

BACKGROUND: The purpose of this study was to compare the safety and efficacy of combined vitrectomy, intravitreal triamcinolone acetonide (IVTA), and bevacizumab injection with that of IVTA and bevacizumab injection and subsequent macular grid laser photocoagulation for the treatment of intractable diffuse diabetic macular edema. METHODS: This randomized controlled clinical trial was performed at Benha University Hospital, Benha, Egypt, and included 34 eyes from 34 diabetic patients diagnosed with intractable diffuse diabetic macular edema without vitreomacular traction. The patients were divided into two groups. In group 1, pars plana vitrectomy with removal of the posterior hyaloid was performed, and at the end of the procedure, IVTA 0.1 mL (40 mg/mL) and bevacizumab 1.25 mg were injected. In group 2, macular grid laser photocoagulation was performed 2 weeks after the same intravitreal injection combination as used in group 1. The main outcome measures were best-corrected visual acuity (BCVA) and central foveal thickness, which were measured using optical coherence tomography at 3, 6, and 12 months. RESULTS: Changes in BCVA and central foveal thickness at 3, 6, and 12 months from baseline were highly statistically significant (P < 0.01). Mean BCVA was better in group 1 at 3 months, nearly equal at 6 months, and less at 12 months. Mean central foveal thickness was more improved in group 1 than in group 2 at 3 months, and was better in group 2 at subsequent measurement points. The major adverse events were development of cataract (more common in group 1) and elevation of intraocular pressure (more common in group 2). CONCLUSION: The combined therapy described here could represent a solution for the treatment of intractable diabetic macular edema, and could have a favorable long-term outcome. Combined treatment of IVTA and bevacizumab plus grid laser resulted in a more favorable reduction in central foveal thickness and improvement in BCVA at 12 months than vitrectomy combined with the same injections. This small study favors the safer, cheaper, and more available line of treatment.