PRINCIPLE CONTRIBUTIONS

After many years of continuous investigation into modification of the cornea (eg, corneal resections for the management of astigmatism, refractive lamellar grafts with and without freezing, the use of a cryolathe),2 two of Professor José Ignacio Barraquer's principle contributions to refractive keratoplasty occurred. In 1964, he introduced keratomileusis (ie, Greek for sculptured cornea)3 and an even more sophisticated technique, keratophakia (ie, Greek for corneal lens).

Keratomileusis. This is an autoplastic procedure for the correction of ametropia. The basis of the operation is to remove, modify, and reinsert the corneal disc into the patient's eye. After fixation with a pneumatic fixation ring, a special microkeratome separates a parallel-faced corneal disk from the anterior layers of the cornea. The microkeratome operates on the principle of a carpenter's plane, shaving the parallel-faced corneal disk,5 which is then frozen and carved with a special lathe according to computer measurements.

PRINCIPLE CONTRIBUTIONS

In the 1970s, Fyodorov saw a young myopic boy with corneal injuries caused by glass fragments. After the injury healed, Fyodorov found the boy's vision was actually better than before the injury. He theorized the radial cuts flattened the cornea. Although a Japanese surgeon had already attempted refractive surgery by making incisions from within the eye, Fyodorov developed radial keratotomy by calculating how to make radial incisions on the anterior surface of the cornea to change its shape. His colleagues did not share his enthusiasm, however. "Slava Fyodorov gave me the original manuscript of refractive keratectomy," Arnott said. "I took it back to England. I sent it off to the editor of the American Journal of Ophthalmology, and they considered it unworthy for publication." Despite opposition, Fyodorov continued to refine the procedure and taught it to others.

PRINCIPLE CONTRIBUTIONS

Three researchers at the IBM ® Thomas J. Watson Research Center in Yorktown, New York—Samuel Blum, Rangaswamy Srinivasan and James J. Wynne—had been exploring new ways to use the excimer laser that had been recently acquired by their laser physics and chemistry group. Blum was an expert in materials science; Srinivasan was a photochemist with 21 US patents to his name; and Wynne was a physicist, who was the manager of the group at IBM. The excimer laser uses reactive gases, such as chlorine and fluorine, mixed with inert gases, such as argon, krypton and xenon. When electrically excited, the gas mixture emits energetic pulses of ultraviolet light, which can make very precise, minute changes to irradiated material, such as polymers.

PRINCIPLE CONTRIBUTIONS

Upon learning of the IBM work, ophthalmologist Stephen Trokel, affiliated with Columbia Presbyterian Medical Center in New York City, came to the Watson Research Center in the summer of 1983 to collaborate on experiments with Srinivasan and researcher Bodil Braren. Trokel, Srinivasan, and Braren wrote a paper introducing the idea of using the laser to reshape or sculpt the cornea (the clear covering on the front of the eye) in order to correct refractive errors, such as myopia or hyperopia. Their paper, published in a major ophthalmology journal in December 1983, launched a worldwide program of research to develop excimer laser-based refractive surgery. New York City ophthalmologist, Steven Trokel made the connection to the cornea and performed the first laser surgery on a patient's eyes in 1987. The next ten years were spent perfecting the equipment and the techniques used in laser eye surgery. In 1996, the first Excimer laser for ophthalmic refractive use was approved in the United States.

PRINCIPLE CONTRIBUTIONS

With the development of precise surgical cutting instruments, the use of the excimer laser could be combined with an incision to produce a particular surgical result. It has become, by far, the most commonly performed refractive surgery procedure used today. During LASIK the surgeon first creates a thin corneal flap using a device called a microkeratome. The corneal flap is lifted up, and the excimer laser beam is applied to the exposed interior surface of the cornea to reshape the tissue. The flap is then replaced over the treated area. This corneal flap serves a natural bandage, which eliminates the discomfort associated with other types of refractive surgery, and expedites the healing process. Because of the extraordinary bonding properties of the corneal tissue, stiches are not needed to keep the flap in place after LASIK surgery.