Over the past century, several refractive surgical techniques have been devised to correct ametropia. These can be categorized in three difterent ways: (I) The first is the "subtraction" method, consisting in the removal of tissue from the patient's cornea1 . Removal is almost always performed on the central optical zone. Mechanical instruments or photoablative lasers are used for these procedures. Today, the ArF I 93nm excimer and, potentially, the 21 3nm frequency quintupled Nd:YAG solid state lasers have replaced the keratomileusis mechanical techniques originally developed by José I. Barraquer; (II) The second is the Nadditivew method, involving the implantation of donor tissue or a polymeric implant in the host corneal stroma1 or under the host comeal epithelium2. One subclassification of the second method consists of implanting a lenticule over the central optical zone while the others rely on bending the host peripheral cornea either using a ring implant; (Ill) The third method consists of thermal shrinking portions of the stromal collagen at difterent locations on the cornea to correct myopia, hyperopia, or astigmatism. Several kinds of heat sources have been investigated, including hot wires cautery and RF diathermy, but the mid-infrared lasers have given the best clinical results thus fare.