The contact lenses should not be shared with other people. As we know, the contact lenses are used to breathe the air through the thin lenses. There may be the protein left on the lenses after a day use of the contact lenses. However, if you share with others, the bacterium will be infected which will easily let your eyes get infection. You'd better not do this.
Well, you are right. Generally speaking, everyone should not share contact lenses with other people. When you share contact lenses with others, it can transmit harmful bacteria. In that way, I have to say that it can lead to eye infection for our eyes are so sensitive that they can be infected easily. Also, in some cases, it can be potentially dangerous eye conditions. For example, it can lead to some other eye diseases, such as the pink eyes, sore eyes, dry eyes. Anyway, it can be very dangerous. Besides, if you are wearing contact lenses, you should be careful about your contacts and also you should clean your hands when take off your contacts. Also, using the resolution is also essential.