AIM: To identify early biomarkers associated with glaucomatous visual field (VF) progression in patients with normal-tension glaucoma (NTG). METHODS: This study included patients were divided into two groups based on disease progression status. Tear samples were collected for proteomic analysis. Data-independent acquisition (DIA) mass spectrometry combined with bioinformatic analyses was performed to identify and validate potential protein biomarkers for NTG progression. Additionally, differentially expressed proteins (DEPs) were evaluated using mediating effect models and receiver operating characteristic (ROC) curve analysis. RESULTS: A total of 19 patients (20 eyes) with NTG participated in this study, including 10 patients (4 males and 6 females; 10 eyes) in the progression group with mean age of 67.70±9.03y and 10 patients (4 males and 6 females; 10 eyes) in the non-progression group with mean age of 68.60±7.58y. A total of 158 significantly differentially expressed proteins were detected. UniProt database annotation identified 3 upregulated proteins and 12 downregulated proteins. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that these DEPs were mainly enriched in pathways such as oocyte meiosis. Gene Ontology (GO) enrichment analysis revealed functional clusters related to cellular processes. Weighted gene co-expression network analysis (WGCNA) indicated that the core proteins were primarily involved in the neurodegeneration-multiple diseases pathway and cellular processes. Mediating effect analysis identified PRDX4 (L) as a potential protein biomarker. ROC curve analysis showed that GNAI1 had the largest area under the curve (AUC=0.889). CONCLUSION: This study identifies 15 differentially expressed proteins in the tear fluid of NTG patients, including PRDX4 (L). PRDX4 (L) plays a key role in oxidative stress.