Long-term outcomes of pars plana vitrectomy with internal limiting membrane removal in diabetic macular edema

PURPOSE: To report the long-term visual results and anatomical outcome as assessed by optical coherence tomography (OCT) after pars plana vitrectomy (PPV) with removal of the internal limiting membrane (ILM) in diabetic macular edema (DME). METHODS: Medical records of 27 eyes of 27 patients who underwent PPV with ILM removal for DME attributable to diffuse leakage were reviewed. This retrospective study included eyes that underwent PPV with ILM removal at our institution with preoperative and postoperative OCT assessment of DME. None of the eyes had OCT evidence of anteroposterior vitreomacular traction. Main outcome measures were foveal thickness and visual acuity changes. RESULTS: Foveal thickness decreased by at least 20% in 22 eyes (81.4%) and increased by at least 20% in 3 eyes (11.1%) with PPV and ILM removal (mean follow-up +/- SD, 27.6 +/- 7.2 months; range, 12-38 months). Mean foveal thickness decrease +/- SD was 178 +/- 164 microm (43.6%), with a mean preoperative foveal thickness +/- SD of 408 +/- 121 microm compared with a mean postoperative foveal thickness +/- SD of 230 +/- 74 microm (P < 0.001). Recurrence of DME was observed at postoperative month 24 in 2 eyes and postoperative month 30 in 1 eye. Visual acuity improved by > or =2 lines in 10 eyes (37%) and decreased by > or =2 lines in 3 eyes (11.1%). Mean best-corrected logMAR (logarithm of the minimum angle of resolution) visual acuity +/- SD was 0.75 +/- 0.35 preoperatively and 0.63 +/- 0.33 postoperatively (P = 0.033). CONCLUSION: PPV with ILM removal appears to be effective in reducing DME and improving visual acuity, and its effectiveness is maintained in the long term. Recurrence of DME may be observed in the late postoperative period.