Contacts are these really really cool people around town who never mistake the letter T for the letter K, and in addition to all that coolness, will make it easier for you to solve cases because they will never clam up on you. Check out the newbie FAQ, which you'll find by scrolling to the bottom of the very screen before you! Little gray letters! How very handy!
There's a whole section there that deals with contacts.
Unless you were looking for lenses. In which case you're gonna have to sleep with an ophthalmologist, or a camera, or something. That'll be a Kodak moment, for real.