Perhaps the most important technology in the ability to perform LASIK eye surgery in San Jose was the invention of the excimer laser. No other medical device used in LASIK surgery is as advanced or has as much influence upon the results of LASIK eye surgery as the excimer laser. A San Jose LASIK surgeon should consider the Excimer Laser to be the single most important piece of equipment that is used in LASIK eye surgery.
While there have been a few laser companies that have experimented with solid state lasers, the majority of lasers used today for LASIK surgery and all of the FDA approved lasers operate at a wavelength of 193 nanometers and are therefore ultraviolet lasers.
The word excimer is short for â€˜excited dimerâ€™, referring to the state of stimulation that is created prior to the laser being fired. The excimer laser is an ultraviolet chemical laser and has been very effective in LASIK eye surgery.
Excimer lasers use a combination of argon (an inert gas) and fluorine (a highly reactive gas). When stimulated, this gas can exist in an energized state which when focused and the energy is release, creates a very precise ray of light that can evaporate biological tissue with an exceptional level of delicacy. The laser light is also considered to be absorbed well and therefore has very little effect on the surrounding tissue.
Rather than burning, heating, or cutting the tissue, the excimer laser adds enough energy at one time to disrupt the molecular bonds of the surface molecules, which effectively evaporate into the air in a reaction that is known as photoablation. The process of photoablation allows the excimer laser to treat the cornea with an accuracy of less than 1 micron. Most importantly, the surrounding tissue has very little heat absorbed and is therefore more or less intact as it was prior to LASIK.
Excimer lasers have grown progressively faster with time, allowing the total LASIK treatment time to be reduced. It is important to reduce the laser time during LASIK in order to reduce the time in which the flap is open and can result in surface dryness. Dryness during LASIK and fluctuations in moisture can cause a level of inaccuracy to be introduced into LASIK surgery.
Many of the Excimer Lasers that are being manufactured are attempting to shorten treatment time without causing excess heating. Obviously firing a laser in areas of close proximity in rapid succession could lead to excess heating and less desirable results. Many of the laser manufacturers (such as Zeiss, Alegretto, and Alcon) have managed to manufacture lasers operating at speed of over 200 Hz.
History of the Excimer Laser
The first excimer laser was invented by Basov, Danilychev and Popov in 1971 in Moscow Russia. They used a xenon dimer that operated at a 172 nm wavelength. Later imporvements in the United States at the United States Governmentâ€™s Naval Research Laboratory made use of a noble gas halide.
In truth, the term excimer laser could be considered a misnomer since the majority of â€œexcimerâ€ lasers are created using the noble gas halides. The term excimer uses the words â€œexcited dimerâ€ which refers to a molecule of two identical or similar parts. The correct term should in fact be the exciplex laser.
Excimer lasers have opened the way for corrective eye surgery in a way that at one time may have been considered impossible. In San Jose, Turner Eye Institute prefers using the AMO VISX Star S4 with Iris Recognition as it provides excellent LASIK results and has been FDA approved for a wide variety of refractive errors with a high degree of success.