Well, yes, it is true that contact lenses can just mess up eyes in some degree, especially when contact lenses are unclean and infected by some bacteria. Generally speaking, contact lenses are made from plastics, and they can be easily infected by some other bacteria. And then it will just make your eyes infected too. And in that way, your eyes may suffer from double vision, and blurry vision. Also, we can say that contact lenses just mess up your eyes. So to avoid this, you just need to keep your contacts clean, and far from some allergies. Also, do not wear contact lenses which are out of using time, or it will just make your situation serious.