Tuesday, April 22, 2008

Lasik - The Technology

From Wikipedia ...

The LASIK technique was made possible by the Colombian-based Spanish ophthalmologist Jose Barraquer, who, around 1950 in his clinic in Bogotá, Colombia, developed the first microkeratome, used to cut thin flaps in the cornea and alter its shape, in a procedure called keratomileusis. He also provided the knowledge about how much of the cornea had to be left unaltered to provide a stable long-term result.

Later technical and procedural developments included the RK (radial keratotomy) started in the '70s in Russia by Svyatoslav Fyodorov and the development of PRK (photorefractive keratectomy) in the '80s in Germany by Theo Seiler.

In 1968, at the Northrup Corporation Research and Technology Center of the University of California, Mani Lal Bhaumik and a group of other scientists, while working on the development of a carbon-dioxide laser, would develop the Excimer laser, where molecules that do not normally exist come into being when xenon, argon or krypton gases are excited. This would form the cornerstone for LASIK eye surgery. Dr. Bhaumik announced his discovery in May of 1973 at a meeting of the Denver Optical Society of America in Denver, Colorado. He would later patent it. [1]

The introduction of Laser in this refractive procedure started with the developments in Laser technology by Rangaswamy Srinivasan. In 1980, Srinivasan, working at IBM Research Lab, discovered that an ultraviolet excimer laser could etch living tissue in a precise manner with no thermal damage to the surrounding area. He named the phenomenon Ablative Photodecomposition (APD).[2]. Dr. Stephen Trokel published a paper in the American Journal of Ophthalmology in 1983, outlining the potential of using the excimer laser in refractive surgeries.

The first patent for LASIK was granted by the US Patent Office to Gholam A. Peyman, MD on June 20, 1989, US Patent #4,840,175, "METHOD FOR MODIFYING CORNEAL CURVATURE", describing the surgical procedure in which a flap is cut in the cornea and pulled back to expose the corneal bed. This exposed surface is then ablated to the desired shape with an excimer laser, following which the flap is replaced.

Using these advances in laser technology and the technical and theoretical developments in refractive surgery made since the 50's, LASIK surgery was developed in 1990 by Lucio Buratto (Italy) and Ioannis Pallikaris (Greece) as a melding of two prior techniques, keratomileusis and photorefractive keratectomy. It quickly became popular because of its greater precision and lower frequency of complications in comparison with these former two techniques. Today, faster lasers, larger spot areas, bladeless flap incision, and wavefront-optimized and -guided techniques have significantly improved the reliability of the procedure as compared to that of 1991. Nonetheless, the fundamental limitations of excimer lasers and undesirable destruction of the eye's nerves have spawned research into many alternatives to "plain" LASIK, including all-femtosecond correction (Femtosecond Lenticule EXtraction, FLIVC), LASEK, Epi-LASIK, sub-Bowman’s Keratomileusis aka thin-flap LASIK, wavefront-guided PRK, and modern intraocular lenses.

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