After the eye drops are opened, depending on the storage environment, try not to use them after half a month. Because after opening the eye drops and air contact, oxidation will occur in the eye drops, making them less effective. In addition, eye drops may be contaminated by bacteria and impurities after contact with the surrounding environment. If the contamination is ordered to the eye, not only can it not play the role of the corresponding drugs, but also may be infected and new inflammation occurs. Therefore, do not consider eye drops left a lot of feeling do not need to throw away, can continue to use, if the complications occur is not worth the loss, so it is recommended that eye drops with half a month before buying a new one for use.