LASIK/History
The History of LASIK
While surgery involving corneal incisions--Keratotomy--began as early as the late 1890's, it was largely experimental (and unsuccessful) until over 50 years later. It wasn't until WWII that the Japanese began experimental surgeries to correct myopia in Asians. The procedure involved a series of incisions in the cornea to cause flattening. As the eye healed, the surface of the cornea would depress, thereby adjusting the patient’s refractive error. Due to the frequent complications and general unpredictability, this early form of refractive surgery was abandoned.
The Early Years
Around the same time, Spanish born Dr. Jose Barraquer began experiments in Columbia with a process he called Keratomileusis. Using a cryolathe, Barraquer would remove the top 60% of the cornea. This ‘cap’ was then frozen and reshaped (as a modern contact lens would be) to achieve the appropriate correction (Note: this specific type of keratomileusis is often referred to as ‘freeze myopic keratomileusis’, or MKM). Once sewn back in place, the cap would heal into the cornea and result in permanent changes to the patient’s eyesight. While far from perfect, Keratomileusis was safer and more accurate than the earlier attempts at refractive surgery made by the Japanese. It is for this reason that Dr. Barraquer is commonly regarded as the father of modern refractive surgery.
During the early 1960’s, keratomileusis was relatively difficult to perform and still delivered unpredictable results. Without modern diagnostic tools, modifications to the surgical process could only proceed by trial and error. Ultimately, several years of experimentation and refinement gave birth to Automated Lamellar Keratoplasty (ALK) in the 1960’s. ALK implemented a similar process to MKM but used a microkeratome to remove precise amounts of corneal tissue, leaving out the freezing, reshaping, and replacement processes altogether. In ALK, the microkeratome cuts a small flap in the surface of the cornea and folds it back to remove a thin disc from the corneal stoma. The thickness and diameter of the removed disc dictate the change in the patient’s refractive error (5).
Despite its improvements in treating myopia over prior forms of refractive surgery, ALK was still largely inconsistent as a procedure and was eventually abandoned in favor of Radial Keratotomy.
Refractive Surgery Takes Root
The latter half of the 1960’s saw a dramatic increase in the popularity of refractive procedures, although success rates were still much lower than with modern technology. This was due, in particular, to the invention of Radial Keratotomy by Russian Ophthalmologist (Fyodorov). Building off of Barraquers’ experiments with keratomileusis, Fyodorov attempted to reshape the cornea without removing any tissue. Using a scalpel, Fyodorov would make a series of radial incisions through 90% of the cornea’s thickness. The number of incisions would depend upon the level of correction needed. As the eye healed, the center of the cornea would depress, causing an effective change in refractive error. Although much more reliable than prior methods, RK was still a manual process. Furthermore, it could only treat a small range of myopia and astigmatism.
The Excimer Laser Era
In the 1970’s the use of diamond knives for radial keratotomy gained even more popularity. Meanwhile, in 1973 ophthalmologist Steven Trokel began testing excimer laser technology and its potential use in conjunction with, or as a replacement for, the microkeratome. Pioneered by the US military, the excimer laser lent itself to refractive surgery due to its extreme precision and low heat emittance.
Dr. Tokel's experiments led to the development of PhotoRefractive Keratectomy, a procedure that is still widely used today as an alternative to LASIK. Although modified excimer lasers were available for ophthalmic uses in the early 1980's, the FDA did not approve their use for PRK until 1995. Still, a year after successful testing on a blind eye (1987), PRK started to gain acceptance as a viable procedure.
The 1980’s are widely considered to be the most significant decade in the history of refractive surgery due to the widespread use and popularity of PRK. PRK marked a vast improvement in precision and predictability over RK, treating an even wider range of prescriptions and refractive errors while altering only 10-20% of the cornea (instead of the 90% needed for RK).
In contrast to ALK and LASIK, PRK removes tissue from the cornea at the surface, without the creation of a corneal flap. This tends to lead to an elongated and more uncomfortable healing period. It was this fact that eventually led to the development of modern day LASIK surgery.
The LASIK Revolution
The 1990’s saw the quest for an equally accurate surgical procedure to PRK without its long and uncomfortable recovery period. LASIK was first conceived as a solution to this problem in 1989 by a Greek doctor, Ioannis Pillikaris. The procedure synthesized both Keratomileusis and PRK and centered on the creation of a corneal flap to enable treatment of the inner areas of the cornea. In the absence of abrasive surface treatment (as in PRK), recovery times with LASIK were significantly improved.
The LASIK procedure was first used on human eyes in 1992. It quickly became the most popular form of refractive surgery, due in large part to it customizability. Unlike prior procedures, LASIK gave the surgeon more control over the possible corrective results of surgery.
Many LASIK procedures still use a microkeratome to create the corneal flap before the excimer laser makes but the trend is toward all laser LASIK.
Currently, the LASIK procedure continues to be refined and improved to be more safe, accurate, and efficient. Most recent developments center on enhancing the laser guidance system via computer.
References
- 1) LASIKMD.ca
- 2) Wikipedia: LASIK
- 3) WestChesterVision.com
- 4) Clario
- 5) Wikipedia: Automated Lamellar Keratoplasty
- 6) Visian Info
> Qualifying For LASIK Surgery
