Purpose:The purpose of the present study was to characterize the idiopathic epiretinal membrane (iERM) through proteomics and phosphoproteomics analysis to facilitate the diagnosis and treatment of iERM. Experimental Design:The vitreous of 25 patients with an iERM and 15 patients with an idiopathic macular hole were analyzed by proteomic and phosphoproteomic analysis based on tandem mass tag. PRM was used to verify the differential proteins.Results: Proteomic analysis identified a total of 878 proteins, including 50 differential proteins. Tenascin-C, galectin-3-binding protein, glucose-6-phosphate isomerase, neuroserpin, collagen alpha-1(XI) chain, and collagen alpha-1(II) chain were verified to be upregulated in iERM by PRM. Phosphoproteomic analysis identified a total of 401 phosphorylation sites on 213 proteins, including 27 differential phosphorylation sites on 24 proteins. Mitogen-activated protein kinase-activated protein kinase (MAP-KAPK)3 and MAPKAPK5 were predicted as the major kinases in the vitreous of iERM.Twenty-six of the differential proteins and phosphorylated proteins may be closely related to fibrosis in iERM. Conclusion and Clinical Relevance:Our results indicated the potential biomarkers or therapeutic targets for iERM, provided key kinases that may be involved in iERM. Fibrosis plays an essential role in iERM, and further exploration of related differential proteins has important clinical significance.