Pars plana vitrectomy with internal limiting membrane peeling for diabetic macular edema

Purpose: To evaluate anatomic and visual acuity (VA) results of pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling for diffuse diabetic macular edema (DME), and to review the literature on the topic. Methods: Retrospective noncomparative case series of patients who underwent PPV with ILM peeling for diffuse DME between January 1, 2000, and December 1, 2005, performed by three surgeons at Bascom Palmer Eye Institute. Main outcome measures included pre- and postoperative optical coherence tomography (OCT) and visual acuity. Mean follow-up period was 8 months (range, 43 days-2 years). Results: Twenty-four eyes of 23 patients meeting the criteria were evaluated. Duration of DME ranged from 1 to 93 months. Mean preoperative logMAR vision was 0.782 (range, 0.30-1.82). Mean logMAR visual acuity at final follow-up was 0.771 (range, 0.10-2.00). At last follow-up, 25% of eyes had >= 2 line increase in VA from baseline, 54% of eyes had no improvement in VA, and 21% of eyes had >= 2 line decrease in VA. Of 9 eyes with pre- and postoperative OCT, there was an overall reduction in central macular thickness of 141 mu m at postoperative month 3 and 120 mu m at last follow-up. Postoperative complications included progression of cataract in 6 (60%) of 10 phakic eyes, postoperative intraocular pressure >= 30 mmHg in 6 (24%) eyes, and postoperative vitreous hemorrhage in 2 (8%) eyes. Conclusions: Pars plana vitrectomy with ILM peeling was associated with a reduction in DME when measured by OCT in the majority of eyes, but visual acuity outcomes showed minimal improvement compared to baseline. These results suggest the efficacy of PPV with ILM peeling for eyes with DME has not been well established and should be reserved for therapy with selected cases.