The History of Ophthalmology
Part 5: The Twentieth Century: Swift Progress
Worldwide discoveries and improvements in the 20th century led to the Wavefront-guided LASIK we know today (Custom LASIK). As with every other aspect of medicine, lasers and computers have opened doors to new procedures, many improvements, and increased safety.
Jose Barraquer and the Microkeratome
The pace of discoveries and improvements started picking up in the 1940s, with Jose Barraquer, a Spanish ophthalmologist. He lived from 1916 to 1998, moving to Bogota, Colombia in 1953. People have long given him the title of “Father of Modern Refractive Surgery”. Perhaps by now, considering the many refinements and improvements made to refractive surgeries in recent years “Grandfather” might be more accurate.
The main “focus” of his work was how the eye focuses – how it refracts light to get clear vision, and how the cornea could be reshaped to improve vision. He founded the Barraquer Institute of America, where he taught ophthalmologists from all over the world how to do his new procedure called Keratomileusis. This is the “K” in LASIK”, which stands for Laser Assisted in situ Keratomileusis.
In trying to devise the best way to reshape the cornea, he invented an implement which is still used in a modified form – the microkeratome. It is a very precise oscillating blade used to create the corneal flap in a LASIK procedure.
Barraquer’s first approach to vision correction was to remove a layer of the cornea, freeze it, reshape it with a lath, and then stitch it back on. For each patient, he at first made his calculations with pen and paper in the operating room. Later he acquired a calculator, which were large objects in those days. He also invented a computer-controlled cryolathe to more effectively freeze and reshape the corneal tissue.
He was aware that each person’s cornea had only a certain thickness, and that not too much should be removed, as that could permanently destabilize the eye. To this day, a person with thinner-than-average corneas is not a good LASIK candidate. But one of the problems with his Keratomileusis was that freezing the corneal tissue damaged it.
Later in his career, Barraquer worked with one of his protégés named Luis Ruiz. Ruiz modified the procedure and automated the microkeratome so that the corneal reshaping was done without removing and freezing any tissue. It was done in situ – another part of our term LASIK (Laser Assisted in situ Keratomileusis). His new procedure was named Automated Lamellar Keratoplasty (ALK).
It was performed through the 1980s and was effective for severe myopia, where the cornea is very steep, and for mild hyperopia, where the cornea needs a slight steepening. Results are more predictable than those of RK (see next paragraph), but many eye doctors still thought a better procedure should be devised, as patients were having flap complications afterwards.
Svyatoslav Fyodorov and Radial Keratotomy (RK)
Meanwhile, in Russia, in the 1970s, a young boy fell off his bicycle and got a piece of glass in his eye from his broken spectacles. He was taken to Fyodorov in hopes that his vision could be saved. Fyodorov made radial incisions in the cornea and successfully removed the piece of glass. A while later, the boy noticed that he could see well in that eye without any glasses.
Fyodorov had just performed the first RK procedure. By making cuts like the spokes of a bicycle wheel he had flattened the boy’s cornea, correcting his eye’s myopic refractive error – too much steepness of curvature. He promptly began working to make the procedure reliable and predictable, and reduced the number of incisions to 16. By varying the number of incisions and the size of uncut corneal areas, he was able to control how much vision correction was done.
He taught all this to visiting U.S. ophthalmologists. As more eye doctors began offering it, metal blades were upgraded to highly-polished diamond blades giving greater precision; and the number of incisions was reduced from 16 to four.
RK is a way of improving vision by altering the corneal curvature, which makes it a conceptual precursor to LASIK. But radial cuts are a different method than the flap and laser corneal ablation of LASIK and its direct precursors. RK is not performed any more.
Fyodorov also tried to treat hyperopia (farsightedness), using a hot needle around the corneal periphery. A hyperopic eye has a cornea that is too flat so that light from close objects is not refracted enough. The hot needle shrank corneal tissue around the edges, which had the effect of steepening its curvature, thus increasing light refraction. The needle was heated to 600 degrees centigrade and made a scorching sound each time it entered the cornea. It became cooler as it entered, so that the external cornea shrank more than the internal cornea. Results were not very predictable.
For 30 years, starting in 1961, an Indian-born IBM researcher named Rangaswamy Srinivasan studied how ultraviolet light acts on organic matter. In the 1980s he began using the pulsed excimer laser and his group discovered that it could etch organic solid materials such as plastics without damaging any surrounding substance. He gave it the name of Ablative Photodecomposition (APD).
While APD went on to many uses in plastics, such as drilling nozzles for inkjet printers, Srinivasan started working with surgeons to see how APD could enhance medical procedures. From this work came the use of the excimer laser in vision correction. In 1983, Dr. Stephen Trokel wrote a paper for the American Journal of Ophthalmology, describing how it could be done, and other doctors worldwide took things from there.
Srinivasan himself still wears glasses – his corneas are too thin for LASIK.
History of Ophthalmology Part 1: The Ancient World
History of Ophthalmology Part 2: The Middle Ages: Spectacles
History of Ophthalmology Part 3: Anesthesia and Infection
History of Ophthalmology Part 4: The Nineteenth Century: Seeing the Eye
History of Ophthalmology Part 6: What is a Laser?
History of Ophthalmology Part 7: Leading up to LASIK
History of Ophthalmology Part 8:LASIK Into the Twenty-First Century