An implantable collamer lens (ICL), also known as an implantable contact lens, is a refractive lens implant that is implanted into the eye to correct short-sightedness (myopia), long-sightedness (hyperopia) and astigmatism. It functions exactly like a contact lens, except that it is surgically implanted into the eye, behind the iris (the coloured part of your eye) and in front of your natural lens. An ICL does not require any maintenance, and stays in the eye until you decide to have it removed.