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

Minhee Cho, Donald J D'Amico

Weill Cornell Medical College, Department of Ophthalmology, New York, NY, USA

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 mm³ preoperatively and 7.5 mm³ 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.

Keywords: chronic macular edema, diabetes mellitus, internal limiting membrane peeling, 25-gauge vitrectomy, uveitis, vein occlusion