Eye drops expired should not be used, mainly because of the following points: 1, eye drops expired, it loses its original efficacy, can not treat the disease, but will delay the disease; 2, eye drops expired, the chemical composition may have changed, easy on the eye drops after the reaction; 3, eye drops expired, the bottle is open for too long, can cause contamination of the bottle, after using, easy to cause infection, resulting in a double Infection, this situation is best not to use. If you find that after the use of rinse both eyes as soon as possible, sometimes there is no special abnormalities after the use, may be that the effect does not occur, but the eye drops expired certainly can not be used.