Millions of Americans wear contact lenses to improve their vision, but a large majority of them also commit a contact faux pas on a regular basis. For example, if you run out of contact solution, using water instead is not a safe substitution for the time being. No matter where you are, water is always going to have some bacteria in it. These microbes are safe for your stomach, not so much for your eyes.
Scientists recommend using new solution in completely-dried contact cases every night. Keeping your contacts clean and germ-free will prevent infections, where in the worst case could end up in blindness. Contacts impair the eye's immune response, and scientists don't know why. Therefore, it's important to keep your eyes as clean as possible to avoid infection.