Allergic conjunctivitis is an allergic reaction of the eye caused by pollen, dust and animal hair. Allergic conjunctivitis is divided into five categories: seasonal allergic conjunctivitis, perennial allergic conjunctivitis, springtime keratoconjunctivitis, atopic keratoconjunctivitis and macropapillary conjunctivitis, with the first two types being more common. Seasonal allergic conjunctivitis is most common in adolescents, mainly due to allergy to plant pollen and mold spores, with seasonal onset and rapid relief or disappearance of symptoms after removal from the allergen, often with a history of allergic rhinitis, asthma, allergic dermatitis, and other allergic diseases. Perennial allergic conjunctivitis is mostly seen in young and middle-aged women, mainly allergic to dust mites, molds, animal fur, etc., with perennial onset and mild symptoms, often accompanied by allergic rhinitis. Patients with atopic keratoconjunctivitis are mostly adult males aged 30 to 50 years old with persistent symptoms, mainly eye itching, astringency, heavy eyelid sensation, and may have corneal changes, mostly with a family history of atopic dermatitis, often accompanied by eczema-like skin changes and asthma. Patients with springtime keratoconjunctivitis are mostly 10-20 years old, mainly onset in spring, self-limiting, mainly persistent eye itching, tearing, foreign body sensation, more aggravated in the evening, more mucous discharge, may have photophobia, and even vision loss. Macropapillary conjunctivitis is mainly characterized by itchy eyes, mucous discharge, history of corneal contact lens wear, prosthetic eyes, corneal surgery, etc. Examination reveals hyperplasia of the giant papillae in the conjunctiva of the upper eyelid, mucous discharge, and in severe cases, eyelid edema and ptosis. Treatment principles for allergic conjunctivitis: non-pharmacologic treatment: avoid contact with allergens, cold and wet compresses to relieve symptoms; pharmacologic treatment: ocular antihistamines/vasoconstrictors, ocular mast cell stabilizers, dual action drugs (antihistamines + mast cell stabilizers), ocular NSAIDs, ocular glucocorticoids, immunosuppressants, artificial tears, and oral antihistamines; surgical treatment. Prevention methods are: reduce the room dust (wall lice and mold, etc.); pay attention to ventilation, keep the room dry; careful cleaning, clean the bedroom furniture with a wet rag; allergic to pollen to avoid the peak of pollen time out, home or car attention to close the doors and windows; best not to have pets, try to avoid their activities in the bedroom; 6, sleep appliances should be carefully organized.