Purpose: To compare anatomic and functional results of pars plana vitrectomy with MLI peeling (group PPV) and pars plana vitrectomy with MLI peeling, intravitreal triamcinolon acetonide 4 mg and macular lasercoagulation (group PPV + TRIAM) in eyes with diffuse diabetic macular edema (DEM).
Methods: In the group PPV eyes underwent PPV with MLI peeling and in the group PPV + TRIAM, PPV with MLI peeling, intravitreal triamcinolon acetonide 4 mg was performed at the end of surgery and macular lasercoagulation 3 weeks after surgery. Best corrected visual acuity (BCVA), central macular thickness (CMT) and macular volume were recorded before, 1, 3, 6 and 12 months after vitrectomy.
Results: Sixty - eight eyes from 59 subjects with DEM non responsive to lasercoagulation or with vitreomacular traction were enrolled, the group PPV 35 eyes and the group PPV + TRIAM 33 eyes. In the group PPV before and 1, 3, 6 a 12 months after surgery mean BCVA were 0,22; 0,21; 0,28; 0,32; 0,30, mean CMT were 497,69 μm; 400,89 μm; 356,46 μm; 346,89 μm; 319,49 μm and mean macular volume were 11,48 mm3; 9,82 mm3; 9,28 mm3; 9,07 mm3, 8,83 mm3. In the group PPV + TRIAM mean BCVA were 0,18; 0,16; 0,23; 0,26; 0,26, mean CMT were 447,82 μm; 276,03 μm; 266,27 μm; 268,36 μm; 251,15 μm, mean macular volume were 10,71 mm3; 8,03 mm3; 8,28 mm3; 7,96 mm3; 7,66 mm3. In both groups statistical significant improvement in BCVA were observed from month 3 (p = 0.0013), in CMT and macular volume from month 1 (< 0.001). To compare both groups, in the group PPV + TRIAM changes in CMT and macular volume in month 1 after combination therapy from baseline were statistical significant, but without statistical significant, change in BCVA (p = 0.229). The major complications after surgery were an elevation of intraocular pressure and cataract surgery, more often in the group PPV + TRIAM (p = 0.153, p = 0.056).
Conclusion: Both surgical technics are effective in the treatment of DEM. Combination therapy PPV, triamcinolon acetonide 4mg and macular lasercoagulation is associated with higher number of complications after surgery (elevation of intraocular pressure and cataract surgery).