PurposeThis study aims to assess retinal vascular changes following internal limiting membrane (ILM) peeling for idiopathic epiretinal membrane (ERM) treatment using optical coherence tomography angiography (OCT-A).DesignA retrospective study was conducted.MethodsA cohort of thirty-nine patients was enlisted for this study. Each participant underwent comprehensive ophthalmological evaluation and OCT-A imaging at baseline, as well as at 1-month and 6-month intervals post-pars plana vitrectomy with ERM and ILM peeling.ResultsPost-surgery, remarkable improvements were observed in best-corrected visual acuity (BCVA) (from 0.335 ± 0.173 to 0.096 ± 0.126 at 6 months), coupled with a notable reduction in central retinal thickness (CRT) (from 460 ± 87 µm to 395 ± 53 µm at 6 months). Additionally, there was a noticeable expansion in the foveal avascular zone (FAZ) perimeter (from 0.099 ± 0.060 mm² to 0.125 ± 0.056 mm² at 6 months). However, there was a decline in vessel density (VD) in the superficial capillary plexus (SCP) (from 46.7 ± 4.4 to 43.8 ± 3.5% at 6 months), contrasted by an elevation in the deep capillary plexus (DCP) (from 45.2 ± 5.5% to 43.6 ± 5.3% at 6 months. Noteworthy correlations were detected between CRT and BCVA, as well as CRT and vascular parameters.ConclusionERM instigates a milieu of changes including SCP crowding and elevation, potentially leading to a falsely augmented density at OCT-A in affected patients. Subsequent surgery results in a release of ERM-induced forces, elucidating the observed decrease in SCP density. Conversely, the DCP appears to be less distorted by the ERM, facilitating gradual vessel reopening after its removal. OCTA provides valuable insights into optimal surgical timing.