Glycosylation is an important post-translational modification of proteins that usually occurs at specific locations within the endoplasmic reticulum and Golgi apparatus. N-glycosylation and O-glycosylation are the most common types of glycosylation modifications. Compared to other post-translational modifications, glycosylation has unique biological significance, including structural complexity and diversity, crucial biological functions, and evolutionary conservation. Glycosylation modifications significantly impact protein stability, cell adhesion and recognition, intracellular signal transduction, and epigenetics, thereby regulating cellular biology and pathogenesis. In recent years, an increasing amount of research has revealed the involvement of glycosylation in the occurrence and development of ocular diseases, including ocular surface diseases, keratoconus, glaucoma, age-related macular degeneration, retinitis pigmentosa, and diabetic retinopathy. Abnormal glycosylation of ocular proteins can induce changes in cell structure and function through mechanisms such as neovascularization, inflammatory response, oxidative stress, and abnormal immune response, thereby influencing the occurrence and development of various eye diseases. By deeply studying the mechanisms of glycosylation in different ocular diseases, new insights and methods can be provided for the early diagnosis and treatment of related ocular diseases. This review summarizes the research progress of glycosylation in ocular diseases to explore the diagnostic and therapeutic significance of regulating protein glycosylation in ocular diseases.