Conjunctivitis, keratitis, and dry eye all fall under the category of ocular surface diseases, and their treatment relies on a wide variety of eye drops, but care should be taken in their use to be able to use one drug, not others at the same time, and there should not be too many types. For example, for viral keratitis, only antiviral drops are sufficient, but some patients and even doctors like to use them together with antibiotic eye drops, which is not necessary. The toxic effects of drugs should be taken into account when using drugs, including the harmful effects of the drugs themselves and the preservatives in the drugs. We usually use a variety of antibiotics, antiviral, hormones and non-steroidal anti-inflammatory drugs and other eye drops, all have a damaging effect on the eye surface, long-term use can lead to drug conjunctivitis, corneal epithelial lesions and so on. Therefore, when using eye drops, choose drugs that are less toxic and do not contain antiseptic wattle as much as possible. In addition, some patients do not go to the hospital, but buy their own eye drops point, which can easily cause drug abuse. For example, some patients always complain of feeling blurred vision and foreign body sensation, and use antibiotic eye drops for a long time, but they do not get better. In fact, many of these people suffer from dry eyes, not conjunctivitis, and only need drops of artificial tears.