Peripapillary and Macular Optical Coherence Tomography Angiography Predictors of Visual Improvement in Patients Treated with Vitrectomy for Idiopathic Epiretinal Membrane

Introduction: We investigated the changes of peripapillary and macular microvasculature in idiopathic macular epiretinal membrane (iERM) eyes before and after pars plana vitrectomy (PPV), aiming to identify potential optical coherence tomography angiography (OCTA) predictors of visual acuity improvement. Methods: Fifty-seven eyes diagnosed with iERM were enrolled and underwent PPV with ERM and internal limiting membrane (ILM) peeling. Data were collected before surgery and during the 12-month postoperative period. OCTA analysis focused on radial peripapillary capillary (RPC) vessel density (VD), superficial and deep capillary plexus (SCP and DCP, respectively). Functional and OCT structural outcomes, including best-corrected visual acuity (BCVA) and macular thickness, were also recorded. Results: Multivariate linear regression analysis revealed that higher preoperative RPC VD, lower SCP VD, and lower BCVA were predictors of postoperative BCVA improvement (p < 0.001, p = 0.047, and p < 0.001, respectively). Throughout the follow-up period, there was an observed increase in intradisc RPC VD, whole-disc VD, and parafoveal DCP VD (all p < 0.001). BCVA and central macular thickness demonstrated significant improvement (p < 0.001) within the first month following vitrectomy, which then stabilized from the third month onward. Conclusions: Preoperative microvascular measurements in iERM patients can forecast postoperative BCVA. OCTA findings reveal that both increased RPC density and reduced SCP density at baseline could serve as predictors of better visual outcomes after surgery. Enhanced RPC density may reflect a healthier optic nerve with greater potential for visual recovery, while a less dense SCP could indicate less iERM contraction, both contributing to more favorable postoperative visual results.