Transconjunctival 25-gauge pars plana vitrectomy and internal limiting membrane peeling for chronic macular edema

BACKGROUND The purpose of this study was to investigate the visual and anatomic outcomes in patients with chronic macular edema who underwent 25-gauge pars plana vitrectomy with internal limiting membrane peeling. METHODS This study was a retrospective chart review of 24 eyes from 21 patients who underwent 25-gauge pars plana vitrectomy and indocyanine green-assisted internal limiting membrane peeling for chronic macular edema. Preoperative and postoperative spectral-domain optical coherence tomography (OCT) was examined for macular thickness and macular volume. Outcomes and variables were analyzed using the two-tailed t-test and Spearman's rank correlation coefficient. RESULTS Twenty-four eyes from 11 men and 10 women of mean age 69 (range 55-84) years were included. Four patients (17%) had chronic macular edema from uveitis, four (17%) from retinal vein occlusion, and 16 (67%) from diabetes. Mean visual acuity was 20/103 preoperatively and 20/87 postoperatively (P = 0.55). Sixty-three percent of the eyes had improved vision (47% better than 20/40), 21% maintained the same vision, and 17% had worse vision. Forty-seven percent of improved eyes and 30% of total eyes gained more than two lines of visual acuity (range -9 to +7 lines). Mean macular thickness was 455 μm preoperatively and 396 μm postoperatively (P = 0.29). Mean macular volume was 7.9 mm(3) preoperatively and 7.5 mm(3) postoperatively (P = 0.51). The strongest predictor of postoperative visual acuity was initial visual acuity (r = 0.673, P = 0.0003). CONCLUSION Even though a majority of patients had improved vision and decreased macular thickening after 25-gauge pars plana vitrectomy with internal limiting membrane peeling for chronic macular edema of various etiologies, the difference in visual acuity or macular thickening did not reach statistical significance.