Keratomileusis is derived from the Greek words keratos (cornea) and mileusis (carving). Literally translated, it is carving of the cornea. Keratomileusis is truly a unique operation: It was the first time that part of an organ was removed, modified, and replaced in its original position. Additionally, keratomileusis represented the first time that a computer was used to determine the amount of surgery required for individuals.

In 1949, José Ignacio Barraquer, MD, of Spain, (Figure 1), in his Bogota, Colombia clinic, refined his ideas on correcting spherical ametropia by performing a lamellar keratoplasty for refractive purposes. In 1958, following the removal of a corneal disc, Dr. Barraquer then performed the first lamellar resection in situ. He used a prototype microkeratome that moved along a ring without guides. By approximately 1962, Dr. Barraquer developed a more accurate microkeratome and invented the suction ring.

Next came the development of the cryolathe. The main difficulty during the flap cut was obtaining good fixation of the disc to the lathe. So, after numerous trials, Dr. Barraquer conceived the thought of freezing the disc (Figure 2). It remained frozen during the lathe process, allowing for good fixation. Dr. Barraquer used computer calculations with the cryolathe representing the first time they were used.

Between 1980 and 1983, Jörg H. Krumeich, MD, of Germany; Casimir A. Swinger, MD, of New Jersey; and J.C. Barraquer, MD, of Spain, developed a new instrument, the BKS 1000 System (Polytech, Darmstadt, Germany) (Figure 3). The difference between this refractive cut and the cryolathe was that the corneal disc remained fresh (ie, nonfrozen). Conceptually, this was an enormous step forward. Shortly thereafter, Luis A. Ruiz, MD, of Colombia, proposed and created in situ keratomileusis (ie, automated lamellar keratoplasty [ALK]) (Figure 4), which involved two superimposed parallel keratectomies using a microkeratome.

In 1983, Steven L. Trokel, MD, of New York, began exploring the possibility of using photoablation with an eximer laser to perform refractive incisions and corneal ablation. Five years later, Marguerite B. McDonald, MD, of New York, and Herbert E. Kaufman, MD, of New Orleans, began clinical trials on PRK. Additionally, Theo Seiler, MD, PhD, of Switzerland, started using the eximer laser with a metal mask, creating the first arcuate astigmatic incisions, then PRK.

In 1989, I presented a new technique of intrastromal keratomileusis using the eximer laser, or photokeratomileusis. In this technique, I advocated performing the refractive correction with laser ablation on either the flap (ie, cap) or in situ and termed the procedure eximer laser intrastromal keratomileusis (ELISK) on the cap or in situ. This technique took advantage of the eximer laser's submicron precision and lack of adjacent tissue trauma.

Between 1990 and 1991, Ioannis G. Pallikaris, MD, of Greece, advocated the first use of the excimer laser in keratomileusis. He built upon the ideas previously developed by Dr. Barraquer, Gholam A. Peyman, MD, of New Orleans and Nikolai P. Pureskin, MD. Dr. Pallikaris presented the concept of the nasal corneal hinge and in situ ablation. The surgeon could then lift the tissue flap, perform an in situ refractive procedure on the underlying stroma, and reposition the flap in its original position. This variation was a major improvement in keratomileusis, making it faster and easier.

Around the same time, Guillermo Avalos, MD, of Mexico, and Ricardo Guimar„es, MD, of Brazil, introduced the sutureless technique. These additional developments not only improved the technique, both as restitutio ad integrum (ie, restoration of health) of tissue and the functional recovery of the patient, but they also significantly decreased the amount of irregular astigmatism induced during the procedure.

In 1996, the LASIK technique was again modified when I began to create the flap vertically (ie, from below/upward) as opposed to horizontally. I termed this technique downup LASIK. The expanded use of the Chiron Hansatome (previously Chiron Vision Corp, Claremont, California; now Bausch & Lomb, Rochester, New York) to create superior hinges has allowed this technique to be commonly used.

LASIK now enjoys the position of being the refractive technique of choice for myopia, hyperopia, and astigmatism in more than 90% of refractive procedures. Now, the standard of care is to use large ablation zones with smooth ablations delivered by small beam flying spot tracking lasers (Figure 5). The bar has been further raised with the use of more sophisticated lasers to perform custom ablations. These are tailored more specifically to an individual's optical defects, as determined by both corneal topography as well as wavefront analysis of the entire optical system. Flap creation with a femtosecond laser rather than a blade for greater safety precision and flexibility is now the standard.

Lucio Buratto, MD, is an ocular specialist at Centro Ambrosiano di Microchirurgia Oculare, in Milan, Italy. Dr. Buratto states that he has no financial interest in the products or companies mentioned. He may be reached at tel: +39 02 6361191; fax: +39 02 6598875; office@buratto.com.