The success of RK set the stage for the further development of corneal refractive surgical procedures. Everyone involved in the development of RK knew that, when the excimer laser became readily available, the procedure would be supplanted, but the stage had been set for broad-scale application of corneal surgery, according to Mr. Corley and Mr. Weinberg.
LAMELLAR refractive surgery
The Cryolathe
In the late 1950s, Professor José I. Barraquer, MD, of Bogotá, Colombia, first described the concept of lamellar refractive surgery—his dream to correct vision by reshaping the anterior curvature of the eye. This process, termed keratomileusis, with time laid the basis for future refractive surgery procedures such as automated lamellar keratoplasty (ALK), lamellar corneal inlays, and LASIK.
Steinway Instrument Company, Inc., collaborated with Professor Barraquer to develop and market the first commercially available microkeratome and cryolathe to perform the early keratomileusis procedures. In this process, surgeons completely removed a lamellar disc approximately 350µm thick and 8mm in diameter. The corneal disc was then placed onto the cryolathe and frozen, and a new shape was carved on the stromal surface. Calculations were made on the world's first available programmable calculator using a program written by Professor Barraquer. The carved cornea was thawed and sutured back onto the eye. This was the first time in medicine when a human body part was removed, improved, and replaced, according to
Mr. Weinberg. In the early to mid-1980s, Lee T. Nordan, MD, led an educational effort by training approximately 200 surgeons worldwide to perform keratomileusis with the cryolathe and microkeratome. Because the procedure was so technically demanding, it was not widely adopted and was generally reserved for extreme cases of myopia and hyperopia.
The Microkeratome
The biggest challenge to surgeons was related to the use of the manual microkeratome, according to Mr. Corley and Mr. Weinberg. Luis A. Ruiz, MD, of Bogotá, Colombia, significantly advanced lamellar refractive surgery by developing the first automated microkeratome, also known by the trade name Automatic Corneal Shaper, or ACS. Steinway marketed the ACS worldwide until Chiron Vision (a company that today is Bausch & Lomb [Rochester, NY]) acquired the marketing rights to the product in 1993. Dr. Ruiz, protégée of Professor Barraquer, termed his procedure automated lamellar keratoplasty or ALK, which he described in 1990. ALK immediately replaced the cryolathe with a unique approach. The microkeratome now passed twice over the cornea, first for flap creation and second to remove a disc of tissue to change the central curvature of the cornea and eliminate refractive error. At that time, approximately 500 surgeons adopted the procedure, many of whom had been performing RK. Ultimately, ALK lacked the necessary precision, but it taught surgeons and industry that it was OK to create corneal flaps. It thus paved the road for LASIK.
A UNION OF INNOVATORS
Mr. Corley and Randy Alexander, both executives at Chiron Vision at the time, invited Mr. Weinberg to join the company. In early 1993, the trio decided to incorporate the microkeratome technology from Steinway into Chiron Vision's expanding refractive surgery education program and thereby promote lamellar surgery.
Mr. Weinberg introduced his friend and “master keratome surgeon,” Stephen G. Slade, MD, FACS, of Houston to the Chiron Vision Educational Team. This group, along with Dr. Casebeer and Richard Lindstrom, MD, of Minneapolis, organized a global teaching program together at Chiron Vision, that used a systemized approach to the process of microkeratome-based lamellar refractive surgery versus assisted ablations. The program was well received, and was instrumental in training more than 6,000 surgeons worldwide.
A drawback to the first microkeratome, which led to its replacement by subsequent models, was that it had to be disassembled and reassembled twice during each procedure. Despite ALK's ability to correct large amounts of refractive error, the Chiron Vision refractive team realized that the procedure was going to have a limited life, because Dr. Ruiz had advanced the refractive predictability of lamellar refractive surgery by incorporating the excimer laser for the removal of central tissue in the refractive step of the procedure. The beauty of the lamellar flap created by the microkeratome is that it allowed for quick healing after replacement, and the addition of the submicron tissue-removal capabilities of the excimer laser allowed for precise refractive corrections on the order of ±0.25 to 0.50D. With ALK, the precision was on the order of ±1.50D. With the marriage of the two devices, laser in situ keratomileusis or LASIK was primed to create a tangible refractive surgery industry worldwide.
THE EXCIMER LASER
In 1993, Chiron Vision acquired the Technolas excimer laser technology from Kristian Hohla, PhD, of Munich, Germany, and Dr. Ruiz thus became one of our customers in Bogotá. A group composed of Dr. Slade; Rick Baker, OD, of Houston; J. Trevor Woodhams, MD, of Atlanta; David Dulaney, MD, of Phoenix; and Mr. Weinberg traveled to Bogotá in 1994 to determine the best refractive procedure—ALK or LASIK.
The aforementioned team devised a study wherein four groups of 10 patients each either underwent ALK or LASIK with excimer ablation on the bed and on the undersurface of a flap. Based on the results of the comparison, they determined that LASIK was going to be the dominant procedure in refractive surgery, because patients experienced no substantial intraoperative pain and because their corneas were clear, they could see well, and they could function regularly 1 day postoperatively. Therefore, Mr. Weinberg and Mr. Corley concluded that surgeons would not perform ALK if they had access to an excimer laser. At that time, the excimer laser had yet to be approved by the FDA. “It was a ‘eureka' moment nevertheless, and, in the practical sense, LASIK was born as a clinical procedure,” Mr. Weinberg said.
LASIK
When the FDA approved the excimer laser in 1995, Mr. Corley and Mr. Weinberg said, many manufacturers were skeptical of LASIK because of their unfamiliarity with the procedure and because they feared that the microkeratome component of the procedure would put their lasers at risk. Surgeon's experience and patients' outcomes with LASIK were successful in convincing them otherwise.
CONCLUSION
The history of refractive surgery and of LASIK in particular, are a classic case of innovation that was strongly resisted at first. Ultimately, the majority of refractive surgeons have adopted LASIK or seen its positive impact, as it has become the dominant corneal refractive procedure performed worldwide. LASIK has altered the field of ophthalmology from one that was completely dependent on third-party reimbursement to one that is moving continuously to more privately provided procedures, a trend that is sure to continue.
J. Andy Corley is Chairman and CEO of Eyeonics, Inc., in Aliso Viejo, California. He was General Manager of Refractive Surgery at Chiron Vision. Mr. Corley may be reached at jacorley@eyeonics.com.
Eric Weinberg is Vice President, Marketing and Professional Affairs at Intralase Corp. in Irvine, California. He was Global Director of Refractive Surgery at Chiron Vision and President of Steinway Instrument Company, Inc. Mr. Weinberg may be reached at eweinberg@intralase.com.
