Functional and Anatomic Outcomes in Eyes With Primary Epiretinal Membranes After Surgical Removal: 5-Year Results of the Pan American Collaborative Retina Study Group

Abstract

Purpose: To report the long-term outcomes of patients undergoing epiretinal membrane (ERM) removal and validate the staging classification of the ectopic inner foveal layer as a prognostic factor for visual outcomes. Methods: A multicenter, retrospective, observational study was conducted of patients with an idiopathic ERM who underwent surgical removal and had follow-up of at least 60 months. Biomarkers from preoperative and postoperative spectral-domain optical coherence tomography scans were qualitatively and quantitatively analyzed. Results: Sixty-five eyes from 64 patients with a mean age of 68.1 years were included. Preoperative ERM staging found 9.2% of patients were stage 1, 15.3% stage 2, 50.7% stage 3, and 24.6% stage 4. At 5 years, the mean best-corrected visual acuity (BCVA) improved from 0.6131 logMAR (Snellen equivalent, 20/82) at baseline to 0.2723 logMAR (Snellen equivalent, 20/37) (unpaired t test; P < .001). The central macular thickness improved from 489 µm at baseline to 347 µm (unpaired t test; P = .001). A final BCVA ≥20/40 was attained by 84.6%, 86.2%, and 47.1% of patients with stage 2, 3, and 4 ERM, respectively. Preoperative ERM staging was associated with preoperative BCVA (1-way analysis of variance [ANOVA]; P = .04) and 5-year postoperative BCVA (1-way ANOVA; P < .001). Preoperative microcystoid macular edema was associated with 5-year postoperative BCVA (unpaired t test; P = .030). The preoperative and postoperative thickness of the ectopic inner foveal layer did not correlate with 5-year postoperative BCVA. Conclusions: Surgical removal of an idiopathic ERM results in long-standing improvement in BCVA, regardless of ERM stage. Preoperative ectopic inner foveal layer ERM staging assesses preoperative and postoperative BCVA. The preoperative presence of microcystoid macular edema was associated with a poorer postoperative BCVA.