PM_2.5 is a fine particulate matter with an aerodynamic equivalent diameter of less than or equal to 2.5 μm, and it is the primary pollutant that causes haze. In recent years, numerous research results have shown that PM_2.5 is associated with various ophthalmic diseases and its pathogenic mechanism is complex. It can disrupt the homeostasis of the tear film and the function of the meibomian glands, leading to dry eye; increase the risk of allergic and other types of conjunctivitis; may cause blepharitis; affect the homeostasis of the corneal epithelium and promote the development of keratopathy; the correlation with cataract is controversial; it is related to the risk of glaucoma; it is associated with age-related macular degeneration; it may also indirectly promote diabetic retinopathy. Prevention and control measures include controlling the level of PM_2.5, strengthening publicity and screening, reducing going out and wearing goggles, etc. PM_2.5 is closely related to ophthalmic diseases, but its specific pathogenic mechanism still requires more research to explore.