There are many causes of ocular redness, including surgery and trauma to the eye, and inflammation of the conjunctiva, cornea, sclera and iris. The most common clinical causes of red eyes are subconjunctival hemorrhage and acute epidemic keratoconjunctivitis due to adenovirus infection. Among them, subconjunctival hemorrhage may be related to hypertension, arteriosclerosis, some unexplained, without treatment, 7-10 days can be self-absorption; adenovirus infection of acute epidemic keratoconjunctivitis generally occur in the spring and summer, 2 weeks is contagious, the general course of the disease 3-4 weeks. The medical term “pink eye” refers to epidemic hemorrhagic conjunctivitis. It is a highly contagious acute conjunctivitis caused by enterovirus type 70, which occurs in the summer and fall. It can develop in one eye or in both eyes. Common symptoms include redness and swelling of the eyelids, redness of the whites of the eyes, tearing, itchy eyes, photophobia, and foreign body sensation. When these symptoms occur, you should seek medical attention and pay attention to self-isolation.