The Evolution of Today’s Most Popular Laser Eye Surgeries

LASIK and PRK have improved vision for millions of people

17 August 2015

This year marks the IEEE Photonics Society’s 50th anniversary as well as the International Year of Light and Light-Based Technologies. Here we present some of its members who developed technologies that manipulated light to advance photography and medicine.

Eyeglasses and contact lenses have become a thing of the past for more than 20 million people thanks to laser eye surgery—a procedure that takes less than an hour and sends patients home the same day. Today’s popular methods, including photorefractive keratectomy (PRK) and laser-assisted in situ keratomileusis (LASIK) came from the development of the excimer laser, a device that can make a precise incision in human tissue while not damaging surrounding cells.

The excimer is a variation on Theodore Maiman’s original ruby laser, but two IEEE members discovered how to use the device for relatively safe, efficient surgery. And the laser itself would not have been possible without the work of two IEEE Fellows who developed its predecessor, the maser.

THE BEGINNING

The maser—short for microwave amplification by stimulated emission of radiation—was developed in 1953 by IEEE Fellow Charles H. Townes, IEEE Life Fellow James P. Gordon, and Herbert J. Zeiger. The device produced a single wavelength of light with little interference from other wavelengths. Its output, however, was noncontinuous, or incoherent. The maser inspired a search for ways to make an optical maser, or laser, that would emit continuous, coherent light.

The first person to develop a working laser was Theodore Maiman. A researcher at Hughes Aircraft Co., in Glendale, Calif., Maiman built his laser in 1960 with synthetic red ruby. The energy that excited the atoms in the laser’s ruby came from a helical photographic flash lamp surrounded by a cylindrical reflector. A rod of ruby placed at the center of a helix received energy from all sides. The device converted the lamp’s white light into a monochromatic red light that was coherent. In 2010 this breakthrough was named an IEEE Milestone in Electrical Engineering and Computing.

THE EYES HAVE IT

Just a year after Maiman’s laser was built, ophthalmologists Charles J. Campbell and Charles J. Koester performed the first laser eye surgery on a patient at Columbia-Presbyterian Hospital, in New York City. They used the laser to destroy—essentially burn off—a retinal tumor. But Maiman’s ruby laser was replaced by a more precise laser developed by three IBM researchers in 1979.

IEEE Member James J. Wynne and his group at the IBM T.J. Watson Research Center, in Yorktown, N.Y., began experimenting with an excimer laser, which incorporated reactive gases such as chlorine and fluorine, mixed with inert gases such as argon, krypton, and xenon. Wynne and his colleagues Senior Member Rangaswamy Srinivasan and Samuel Blum discovered that, when electrically excited, this gas mixture emitted energetic pulses of ultraviolet light that could make very precise, minute indentations to polymer material that were smaller than those the ruby laser could produce.

They decided to test the laser on animal tissue. According to an article about the experiment on IBM’s website, Srinivasan brought leftover turkey bones and cartilage into the lab on 27 November 1981—the day after the U.S. Thanksgiving Day holiday. With very short pulses of ultraviolet light, the excimer laser made a clean incision in the cartilage. And when the researchers peered at a piece of the cartilage under the microscope, they noted the surrounding tissue was not burned or charred. It would be almost another year before Wynne worked up the courage to try the laser on a human being—himself. He experimented on his pinky finger. “Each pulse of the laser ablated a thin layer of my tissue, yet there was no sensation of heat or pain,” he wrote in the article.

In 1983, Srinivasan and Bodil Braren, another IBM researcher, collaborated with Dr. Stephen Trokel, an ophthalmologist in New York City, to experiment with the excimer laser on corneas from slaughtered cows. It produced clean microsurgical incisions with no evidence of damage to surrounding cells and tissue.

The three went on to develop an apparatus for performing laser microsurgery on human eyes—essentially the device that today’s PRK and LASIK surgical procedures rely on. In 1989, Trokel’s colleague Dr. Marguerite McDonald used the machine to perform the first PRK procedure on a patient in Germany. With this method, the ophthalmologist scans the patient’s retina with low-power lasers and sends data to a computer, which creates a topographic map of the person’s cornea.* Based on that data, incisions are made with an excimer laser to reshape the stroma, or middle layer of the cornea, to correct such vision problems as myopia (nearsightnedness) and astigmatism (imperfection of the curvature of the eye). Today, the process is automated—the doctor moves the laser across the person’s eye while a computer determines exactly where and how deep each incision should be, and then controls the operation of the laser.

LASIK surgery was developed in 1985 by Gholam A. Peyman, a professor of ophthalmology at the University of Illinois, Chicago. Though it is similar to PRK, there is one significant difference: At the start of surgery, the ophthalmologist makes a thin slice in the outer cornea with the excimer laser and opens it like a flap before using the excimer to make incisions in the stroma. LASIK was approved by the U.S. Food and Drug Administration in 1999 and is today’s most common procedure for laser eye surgery.

*This article has been corrected.

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