Impact of glaucoma on outcomes after epiretinal membrane surgery. a pairwise and post-hoc single-arm meta-analysis

To evaluate whether glaucoma modifies functional, anatomical, and intraocular pressure outcomes after pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling for idiopathic epiretinal membrane (ERM). PubMed, Embase, and Cochrane Library were searched through April 27, 2025, for comparative studies of PPV with ILM peeling in glaucomatous versus non-glaucomatous eyes. Primary outcome was the change (Δ) in best-corrected visual acuity (BCVA); secondary outcomes were changes (Δ) in central macular thickness (CMT), intraocular pressure (IOP), and number of glaucoma medications. Risk of bias was assessed with ROBINS-I and certainty of evidence with GRADE. A post-hoc single-arm synthesis summarized outcomes in glaucomatous eyes. PROSPERO registration: CRD420251041680. Six studies (779 eyes: 256 glaucomatous, 523 non-glaucomatous) contributed to the pairwise meta-analysis, and three additional studies (325 glaucomatous eyes) informed single-arm data. Non-glaucomatous eyes achieved greater BCVA improvement (mean difference − 6.95 ETDRS letters; 95% CI − 11.54 to − 2.35; p < 0.01) and larger CMT reduction after outlier removal (+ 39.50 μm; 95% CI 11.48 to 67.53; p = 0.006). Glaucomatous eyes still improved significantly (BCVA + 10.03 ETDRS letters; CMT − 102.05 μm), with stable IOP (Δ + 0.64 mmHg; p = 0.12) but increased medication use (+ 0.61 drops; p < 0.001). Follow-up ranged from 6 to 12 months, and overall evidence certainty was high. Glaucoma attenuates, but does not eliminate, the visual and anatomical benefits of ERM surgery. However, central visual field safety cannot be guaranteed, particularly in moderate to advanced disease. Careful postoperative glaucoma monitoring and individualized management are recommended.