Modified Grid Laser Photocoagulation Versus Pars Plana Vitrectomy With Internal Limiting Membrane Removal in Diabetic Macular Edema ATES YANYALI, MD, AHMET F. NOHUTCU, MD, FATIH HOROZOGLU, MD, AND ERKAN CELIK, MD ● PURPOSE: To compare the effectiveness of pars plana vitrectomy (PPV) and removal of the internal limiting membrane (ILM) with modified grid laser photocoagula- tion in diabetic macular edema. ● DESIGN: Randomized, comparative, interventional study. ● METHODS: In this prospective study, 24 eyes of 12 patients with bilateral diabetic macular edema were eval- uated. PPV with removal of the ILM was performed at random in one eye of 12 patients (ILM group), and a single session of modified grid laser photocoagulation was performed in the fellow eyes (grid group). Main outcome measures were the foveal thickness measured with opti- cal coherence tomography, preoperative, and postopera- tive visual acuities. Mann-Whitney U and Wilcoxon tests were used in statistical analysis. ● RESULTS: All patients were followed up for 6 months. In the ILM group, mean foveal thickness was 439.2  106.5 m preoperatively and 219.8  63.2 m postop- eratively (P  .002). In the grid group, mean foveal thickness was 407  100.2 m preoperatively and 378.5  141.6 m postoperatively (P  .433). A mean decrease in foveal thickness was found to be 219.4  127.6 m in the ILM group and 28.5  90.5 m in the grid group (P  .001). In the ILM group, best-corrected logMAR visual acuity was 0.75  0.41 preoperatively and 0.53  0.41 postoperatively (P  .006). In the grid group, best-corrected logMAR visual acuity was 0.59  0.27 preoperatively and 0.49  0.27 postoperatively (P  .058). Visual acuity improved by 2 or more lines in six eyes (50%) in the ILM group and in three eyes (25%) in the grid group. Visual acuity remained stable in six eyes (50%) in the ILM group and in nine eyes (75%) in the grid group. ● CONCLUSIONS: PPV with ILM removal appears to be more effective than a single session of modified grid laser photocoagulation in the treatment of diabetic macular edema. Further studies with a large number of patients are required for a more reliable conclusion. (Am J Ophthalmol 2005;139:795– 801. © 2005 by Elsevier Inc. All rights reserved.) D IABETIC MACULAR EDEMA IS THE MAJOR CAUSE of visual loss in diabetic patients. 1 The Early Treatment Diabetic Retinopathy Study Research Group has shown that focal laser photocoagulation reduces the risk of moderate visual loss by 50% in eyes with clinically significant diabetic macular edema. 2 In diabetic macular edema, it has been reported that grid laser pho- tocoagulation stabilizes or improves best-corrected visual acuity in 75.4% of eyes, whereas 24.6% of eyes experience loss of vision after 3 years’ follow-up. 3 In recent studies, pars plana vitrectomy (PPV), with or without internal limiting membrane (ILM) removal, has been reported to decrease macular edema and to improve visual acuity in patients with diabetic macular edema 4–8 The purpose of this prospective study was to compare the effectiveness of modified grid laser photocoagulation and PPV with removal of the ILM in diabetic macular edema. PATIENTS AND METHODS IN THIS PROSPECTIVE STUDY, 24 EYES OF 12 PATIENTS WITH bilateral diabetic macular edema were evaluated between May 2002 and April 2004. Diabetic macular edema was defined as retinal thickening of two or more disk areas involving the foveal avascular zone with or without cystoid Accepted for publication Dec 3, 2004. From the Department of Ophthalmology, Haydarpasa Numune Edu- cation and Research Hospital, Istanbul, Turkey. This study was presented at the meeting of the European Vitreo Retinal Society, Istanbul, Turkey, September 2004. Inquiries to Ates Yanyali, MD, Topagac sok, Akarsu Apt. No. 3/13, Caddebostan, Turkey; fax: + (90) 212 275 40 64; e-mail: ayanyali@hotmail. com © 2005 BY ELSEVIER INC.ALL RIGHTS RESERVED. 0002-9394/05/$30.00 795 doi:10.1016/j.ajo.2004.12.017