Conjunctivitis can be caused by microbial infections, allergies, physical and chemical stimuli, etc. The main manifestations are foreign body sensation, burning sensation, heavy eyelids, increased secretions, photophobia, lacrimation and varying degrees of vision loss when the lesion involves the cornea. 1. Microbial infections: The more common causes of conjunctivitis are viral, bacterial and chlamydial infections, which can be caused by inattention to eye hygiene, frequent rubbing of the eyes with both hands or close contact with patients with conjunctivitis. Allergies: Conjunctivitis is caused by a hypersensitive immune response of the patient’s conjunctiva to allergenic stimuli, common allergens include hair, pollen, dander, etc.; 3. Physical and chemical stimuli: Conjunctivitis is caused by physical factors such as sand, smoke, ultraviolet light, or chemical stimuli such as toxic gases and medical drugs; 4. Spread: If inflammation occurs in other adjacent parts of the patient including cornea, sclera, eyelids, nasal cavity, etc., it may spread to the conjunctiva and conjunctivitis may occur; 5. Secondary to systemic diseases: For example, tuberculosis, syphilis, thyroid disease, Kawasaki disease, etc., can manifest in the conjunctiva and need to be clarified after timely medical examination; 6. Other: Eye tumors, blocked tear ducts and other diseases may also cause conjunctivitis. The diagnosis needs to be made by combining symptoms, medical history and relevant examinations. In daily life, patients with conjunctivitis should pay attention to hand hygiene, develop the habit of washing hands regularly, do not rub their eyes with dirty hands, cut their nails regularly, do not use common towels, washbasins, etc.