History of LASIK Surgery
Where did it all start?
How did refractive surgery elevate itself to such a popular level? Within recent years we have seen the rapid infusion of new technologies in eye care leading to the initial Radial Keratotomy (RK) and evolving towards Wavefront-driven LASIK and then into refractive intraocular surgery. The ophthalmology community has been involved with refractive surgery for over a century now, but it is the recent technology driven times that have generated the most substantial results.
Modern refractive surgery has been improving vision and improving the lifestyle of these patients. Many LASIK patients today do not require glasses of any type and sing the praises of LASIK eye surgery as "truly amazing". But how is it possible to actually shape eyes with surgical techniques? The answer to this question lies ahead in the text below.
The Beginning of Refractive Surgery
L.J. Lans of The Netherlands was the first to design the basic principles of keratotomy in 1898. T. Sako and K. Akiyam of Japan further explored keratotomy in a controlled clinical environment in the 1940s. The general concepts involved radial incisions on the surface of the cornea.
In the 1960s in the USSR, Slava Fyodorov dramatically increased the safety of what was now called Radial Keratotomy (RK) by placing the multiple incisions on the anterior surface of the eye and leaving a clear central optical zone. He observed that predictable results could be obtained by using steel surgical blades and a standardized formula of correction. In the late 1970s interest in RK spread to the United States prompting the nationwide PERK study sanctioned by the National Eye Institute. Results of this study demonstrated the effectiveness of RK but also noted a disturbing percentage of patients with progressive surgical effect and fluctuating daily vision.
Introduction of Refractive Surgery in the United States
In 1978 a refractive procedure called Radial Keratotomy (RK) was introduced in the United States. The RK procedure involves making of a number of cuts in the cornea to change its shape and correct refractive errors. This was the same technique that Dr. Fyodorov had perfected in the Soviet Union. Although RK was not a perfect procedure it quite routinely decreased the complete dependence on glasses.
After the introduction of the RK and PERK study doctors corrected nearsightedness, farsightedness, and astigmatism using various applications of incisions on the cornea. In order to correct astigmatism doctors created AK (Astigmatic Keratotomy) with different nomogram patterns to deal with the irregularities. Improvements in RK surgical technology by the use of ultrathin diamond micrometer cutting blades, microscopic guidance systems, and computer databases for results tracking and predictive nomograms, helped the procedure become increasing popular in the early 1990s. The Caspere Research foundation run by Dr. Charles Caspere helped educate practices throughout this time period and helped to increase public awareness of the procedure.
Making the Leap to PRK (Photorefractive Keratectomy)
In the 1980s a new type of laser, the excimer laser, was developed. This revolutionary laser was originally used to work with the making of computer chips. Ophthalmologists began using the excimer laser successfully in refractive surgery techniques to remove very precise amounts of tissue from the eye's surface. Excimer lasers revolutionized refractive surgery by providing a degree of
safety and precision that was previously unattainable with other techniques.
Charles Brau and James Ewing began researching the use of the excimer laser in 1973. Stuart Searles produced the first excimer laser action in 1975; and Tachisto created the first commercial system in 1979. Taboada, Mikesell, and Reed performed procedures on the anterior corneal surface in 1981. In 1983 Stephen Trokel presented a paper describing the potential of the excimer laser for performing photorefractive keratectomy (PRK) on humans. Shortly after the first experiments were soon performed by Trokel and R. Srinivasan. Then in 1985 and 1986 two companies were formed: VISX and Summit Technology, Inc. These two companies introduced the excimer laser to the ophthalmology community in the US.
The Excimer Laser
This revolutionary laser was originally used to work with the making of computer chips. The excimer laser is a specific type of "cool" laser that generates its power from light in the ultraviolet range. The human eye cannot visualize it. Because the laser does not generate any heat, there is no tissue damage as the result of the laser light. The energy of the laser simply causes miniscule amounts of corneal tissue to dissociate a microscopic level. As the treatment with the laser proceeds microscopic layers of tissue, approximately 1/10th the width of a human hair, are removed. The laser is programmed to remove precisely the amount of tissue needed to achieve the desired result.
After a series of clinical studies, the United States FDA finally approved the use of the Summit laser for PRK correction of myopia in 1995; approval for the VISX laser was granted later in 1996. A year later, the FDA approved the use of the VISX laser for the correction of myopic astigmatism. The Food and Drug Administration of the United States approved the excimer laser for Photorefractive Keratectomy (PRK) in October 1995, for the purpose of correcting nearsightedness. The procedure of PRK reshapes the human cornea by application of laser energy to its front surface, producing a flattening effect. Approval was based on clinical trials of more than 1600 eyes followed for three years. Additional consideration was given to studies from Canada and Europe, where the procedure has been performed since 1987.
The Advent of LASIK (Laser Assisted In Situ Keratomileusis)
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, stitches are not needed to keep the flap in place after LASIK surgery.
