Abstract: Immunoglobulin G (IgG) N-glycosylation is a critical post-translational modification whose structural diversity significantly influences the effector functions of IgG. The biosynthesis of IgG N-glycosylation involves the coordinated action of multiple enzymes in the endoplasmic reticulum and Golgi apparatus. With advances in glycomics analysis techniques, research on IgG N-glycosylation in ocular diseases has attracted considerable attention. In diabetic retinopathy, decreased levels of IgGgalactosylation, fucosylation, and sialylation may contribute to microvascular damage and neuroretinopathy by enhancing complement activation and inflammatory responses. In age-related macular degeneration, disease progression is accompanied by dynamic changes in glycosylation patterns, with immunomodulatory alterations observed in early stages and pronounced pro-inflammatory features in advanced disease. In neuromyelitisoptica spectrum disorders, reduced IgGgalactosylation is associated with disease severity during acute phases, and specific glycoform alterations in the Fc and Fab regions of IgG can effectively differentiate neuromyelitisoptica spectrum disorders from multiple sclerosis. IgG N-glycosylation not only provides a new perspective for understanding the immune-inflammatory mechanisms underlying ocular diseases but also demonstrates potential as a biomarker for disease diagnosis, staging, and differential diagnosis.

Key words: IgG, N-glycosylation, Eye diseases, Biomarker