When eye drops for conjunctivitis are used, if there is localized stinging pain, consider that it may be an adverse reaction to the drug. This is because any drug can have adverse reactions, including eye stinging, eye redness, and mild vision loss. If the symptoms last for a short period of time, for example, only a few seconds or less than a minute, there is generally no need to worry too much because it will not affect the eyes any more and, therefore, does not affect the use of the drug. However, if the symptoms persist for a long time, such as several days in a row or every time the symptoms appear in the eye, and more than once, this situation is considered to be a serious adverse reaction, the use of this drug should be temporarily stopped, or replaced by another eye drops, and after the adverse reaction, you need to go to the hospital to check.