Choosing a surgeon that is experienced and skilled in the LASIK procedure increases the likelihood of having a positive outcome.
LASER EYE SURGERY
Laser Eye Surgery Improves Vision
The purpose of laser eye surgery is to correct refractive errors and reduce a person’s dependency on glasses or contact lenses. The procedure uses a laser to reshape the cornea, the clear outer layer of the eye, in order to change the eye’s focusing power and improve vision. There are many types of laser eye surgery, but the most common and well-known type of laser eye surgery is LASIK. LASIK is used to treat myopia (nearsightedness), hyperopia (farsightedness), and astigmatism (distorted vision).
The Development of LASIK
LASIK is an acronym for Laser Assisted In-Situ Keratomileusis. “Keratomileusis” is derived from two Greek words that literally mean “to shape the cornea.” “In-Situ” means “in place.” Thus, the term LASIK means “to reshape the cornea in place using laser.”
The LASIK procedure is the combination of two sophisticated techniques of surgery with the purpose of correcting refractive errors. The first technique uses a knife, called a microkeratome, to cut a thin layer in the cornea, leaving a hinge at one end of the flap. The flap is folded back to reveal the middle section of the cornea, called the stroma, the area to be sculpted by the laser. Cutting a flap allows for a rapid recovery of vision and reduces discomfort after surgery. The second technique uses pulses from a computer controlled Excimer laser (a cold, invisible, ultraviolet laser) to sculpt the underlying cornea by vaporizing a portion of the stroma and correcting the refractive error. Then the flap is replaced.
The first LASIK laser eye surgery performed in the United States was in 1991. Before LASIK, earlier techniques of refractive surgery were used to reshape the cornea. The most important procedures were Radial Keratotomy (RK) and Photorefractive Keratectomy (PRK). The evolution of LASIK occurred in the search for a better form of refractive surgery to eliminate some of the limitations, risks, and complications of these earlier techniques.
Radial Keratotomy (RK)
The first practical application of Radial Keratotomy (RK) resulted from the occurrence of an eye accident. In the 1970’s, Dr. Fyodorov of Russia was treating a boy whose glasses had broken and cut his cornea. When the boy’s eyes had recovered, his refraction was significantly less myopic than it was before the injury. Dr. Fyodorov researched past efforts in refractive surgery and eventually worked out a more predictable formula for refractive surgery.
The Radial Keratotomy (RK) procedure involves using a series of peripheral cuts (incisions) radiating from the central cornea, with the result of flattening the central cornea. RK can only correct low degrees of myopia and astigmatism. In 1978, American ophthalmologists became interested in Dry. Fyodorov’s findings. After visiting Dry. Fyodorov in Russia, Dr. Leo Bores brought the technology back to the United States.
The Excimer laser is a device that generates high-energy, cold, ultraviolet pulses. It is a unique type of light that does not cut bodily tissue, but rather weakens the molecular bond of tissue cells until the surface tissue disintegrates. When applied to laser eye surgery, the pulses are delivered to the surface of the eye’s cornea, literally vaporizing away eye tissue in order to reshape the cornea, one microscopic layer at a time.
During laser eye surgery, the Excimer laser is computer controlled and programmed to custom treat each individual eye with a high degree of precision. The Excimer laser is noted worldwide for itâ€™s safety and effectiveness.
Although the Excimer laser is now used for laser eye surgery, it was originally used for etching silicone computer chips in the 1970’s. While working in the IBM research laboratories during 1980 to 1983, Dr.’s Rangaswamy Srinivasin, James Wynne, and Samuel Blum, discovered the potential of the Excimer laser in relation to biological tissue interactions. They realized the laser could remove targeted tissue without causing any heat damage to the surrounding material.
Dr. Steven Trokel, a New York City ophthalmologist, made the connection for reshaping the corneal tissue and patented the Excimer laser for vision correction. He performed the first laser surgery on a patient’s eyes in 1987. Over the next ten years, the techniques and equipment for laser eye surgery were perfected. In 1996, the first Excimer laser for refractive surgery was approved for use in the United States.
Photorefractive Keratectomy (PRK)
Photorefractive Keratectomy (PRK) was the first surgical procedure developed to reshape the cornea using a laser. In PRK, the top layer of the cornea, called the epithelium, is scraped away to expose the stroma layer underneath. Because there are nerve fibers in the epithelium, there may be some initial discomfort equivalent to a badly scratched eye. This can further cause pain, irritation, watering of the eye, blurry vision, or the feeling of a particle in the eye. An eye bandage is worn to reduce the irritation and encourage healing of the tissue. Following PRK, vision is blurry for a few days, but improves as the corneal epithelium heals. Vision is often reasonably good at one week and stabilized by six months.
LASIK evolved from PRK and both surgeries use an Excimer laser in a similar manner. The major difference between the two surgeries is the way that the stroma, the middle layer of the cornea, is exposed before it is vaporized with the laser. In LASIK, a flap is cut in the stroma layer, which is folded back for the surgery, then replaced after the use of the laser. Since LASIK does not disturb the sensitive top layer of the cornea there is less discomfort and a faster recovery than with PRK, and the visual benefits are the same.
The LASIK procedure was developed in 1990 by Dr. Lucio Buratto (Italy) and Dr. Ionnis Pallikaris (Greece), combining two known surgical procedures, Keratomileusis and Photorefractive Keratectomy. They were the first to use a microkeratome to cut a thin flap of cornea and then apply the Excimer laser to remove tissue from the cornea. The microkeratome had been used successfully in South America for about 30 years, but had not been used in combination with the laser. It was Dr. Pallikaris that suggested the name Laser In-Situ Keratomileusis (LASIK) for this procedure. In 1991, Dr. Stephen Slade performed the first LASIK procedure in the United States.
LASIK is now the most commonly performed refractive surgery procedure.