Optimal Timing for Idiopathic Epiretinal Membrane Peeling Surgery Based on a Preoperative Visual Acuity Threshold

INTRODUCTION: The aim of the study was to evaluate the efficacy and safety of vitrectomy-peeling for idiopathic epiretinal membrane (iERM) in patients with preserved preoperative best-corrected visual acuity (BCVA) compared to those with reduced BCVA and determine the optimal preoperative VA threshold for intervention. METHODS: This single-center retrospective cohort study analyzed 415 eyes from 368 patients who underwent iERM surgery between January 2019 and July 2023. Epidemiological, surgical, and spectral domain-optical coherence tomography data were collected preoperatively and at each follow-up visit. Patients were divided into three groups based on preoperative BCVA: poor (≤60 Early Treatment Diabetic Retinopathy Study [ETDRS] letters), moderate (61-76 ETDRS), and good (≥77 ETDRS). The primary outcome was final BCVA at the last visit, while secondary outcomes included analyzing surgical complications and preoperative predictive factors to develop a predictive model of postoperative BCVA. RESULTS: Median preoperative BCVA was 75 ETDRS letters (IQR 70-80), improving significantly postoperatively to 80 ETDRS (IQR 75-85) (p < 0.001). BCVA improved across all groups: from 60 to 67.5 (IQR 60-77) in the poor group (p < 0.001), from 70 to 80 (IQR 75-83.5) in the moderate group (p < 0.001), and from 80 to 82 (IQR 80-85) in the good group (p < 0.001). The optimal preoperative BCVA threshold was 75 letters, through an iterative process increasing in 5 ETDRS letter increments, with no significant differences in complications between groups (p = 0.81). CONCLUSION: Patients with good preoperative BCVA achieved better final BCVA. Performing vitrectomy-peeling for idiopathic ERM at BCVA >75 ETDRS letters leads to optimal visual outcomes without increasing complications.