AIM: To observe the characteristics of best corrected visual acuity(BCVA), microperimetry(MP), multifocal electroretinogram(mfERG), and optical coherence tomography angiography(OCTA)parameters in patients with idiopathic epiretinal membrane(IERM), and conduct a comparative study and correlation analysis on these parameters.METHODS:This was a cross-sectional study. A total of 56 patients(56 eyes)diagnosed with IERM who visited our hospital between February 2021 and November 2024 were collected as IERM group, and 33 healthy individuals(33 eyes)undergoing physical examinations were included as control group. Parameters were compared between the IERM group and the control group, as well as among IERM subgroups at different stages. Additionally, correlations among visual function parameters and between these visual function parameters and vascular structural OCTA parameters were analyzed.RESULTS: The general data of patients in the control group and IERM group were comparable. In the IERM group, BCVA, retinal sensitivity(RS), P1 wave amplitude in ring 1, superficial capillary plexus parafoveal vessel density(SCPpfvd), deep capillary plexus parafoveal vessel density(DCPpfvd), and the foveal avascular zone(FAZ)area were significantly lower than the control group(all P<0.01). In contrast, central retinal thickness(CRT), superficial capillary plexus foveal vessel density(SCPfvd), and deep capillary plexus foveal vessel density(DCPfvd)were significantly increased(all P<0.001). When comparing different stages of IERM, significant differences were observed in BCVA, CRT, RS, SCPfvd, and FAZ(all P<0.01). In eyes affected by IERM, BCVA(LogMAR)was negatively correlated with RS; P1 wave amplitude in ring 1 positively correlated with P1 wave implicit time in ring 1; SCPfvd positively correlated with BCVA(LogMAR)and negatively correlated with RS; DCPfvd negatively correlated with P1 wave implicit time in ring 1; and DCPpfvd positively correlated with RS(all P<0.05).CONCLUSION: Eyes with IERM exhibit abnormalities in visual function parameters and vascular structure, with varying degrees of alteration in BCVA, CRT, RS, SCPfvd, and FAZ across different stages. Comprehensive evaluation of BCVA, MP, mfERG, and OCTA contributes to a deeper understanding of the nature of IERM and aids in formulating appropriate diagnosis and treatment plans.