To evaluate the effect of posterior sub-Tenon triamcinolone acetonide injection combined with vitrectomy for idiopathic epiretinal membrane (ERM).

This study included 40 eyes of 40 patients who underwent vitrectomy and membrane peeling for idiopathic ERM. Triamcinolone acetonide (40 mg) was injected into the posterior sub-Tenon space following vitrectomy in 20 eyes of the injected group. The other 20 eyes that did not receive the injection were selected as the control group to match preoperative visual acuity and central macular thickness with the injected group. Pre- and postoperative best-corrected visual acuity, central macular thickness, intraocular pressure, and complications were compared between the 2 groups.

The average visual acuity in the injected group improved from 0.56 ± 0.23 (log MAR) at baseline to 0.52 ± 0.36 at 1 month, 0.44 ± 0.39 at 3 months, and 0.38 ± 0.41 at 6 months postoperatively. Central macular thickness decreased from 456.2 ± 86.2 to 399.0 ± 60.1 at 1 month, 377.1 ± 71.5 at 3 months, and 353.1 ± 57.4 at 6 months postoperatively. In the control group, average visual acuity improved from 0.56 ± 0.23 at baseline to 0.53 ± 0.25 at 1 month, 0.41 ± 0.20 at 3 months, and 0.37 ± 0.24 at 6 months postoperatively. Central macular thickness decreased from 456.4 ± 74.8 to 394.9 ± 63.5 at 1 month, 377.2 ± 56.8 at 3 months, and 358.0 ± 57.2 at 6 months postoperatively. Significant differences in visual acuity and central macular thickness were not observed between the 2 groups before surgery and during the follow-up period. Intraocular pressure and complications were similar.

Posterior sub-Tenon injection of triamcinolone acetonide combined with vitrectomy for idiopathic epiretinal membrane did not affect postoperative anatomical and functional outcomes.