Rangaswamy Srinivasan
Rangaswamy Srinivasan, James Wynne and Samuel Blum invented excimer laser surgery. Their work led to revolutionary laser refractive surgical techniques including photorefractive keratectomy (PRK) and laser-assisted in situ keratomileusis (LASIK), improving vision for millions of people around the world.
Srinivasan was born in Chennai, India, in 1929. He earned his bachelor’s degree in 1949 and his master’s degree in 1950, both in science, from the University of Madras. In 1953, he moved to the U.S. to attend graduate school at the University of Southern California, where he completed his doctorate in physical chemistry in 1956. Though he focused his thesis on protein chemistry, he also began taking an interest in photochemistry. He completed a two-year postdoctoral fellowship at the California Institute of Technology, followed by a research fellowship at the University of Rochester.
In 1961, Srinivasan joined IBM’s T.J. Watson Research Center. Here, he began working with his co-inventors Wynne and Blum. Though he briefly left the company in 1966 to join the faculty at Ohio State University, he returned to IBM in 1967 and remained there until his retirement.
At IBM, Srinivasan studied the action of ultraviolet photons on organic molecules. His research ranged from the photochemistry of small organic molecules such as 1,3- butadiene to synthetic organic polymers that were used as photoresists to manufacture computer chips. When ultraviolet (UV) excimer lasers became commercially available in 1980, he extended his knowledge of synthetic organic polymers into the action of UV pulses on organic solids.
The day after Thanksgiving in 1981, Srinivasan brought some leftover turkey to work. He and his colleagues, Wynne and Blum, began testing the new UV excimer laser on a piece of cartilage from the turkey leg. The cartilage provided a surface that was both smooth, like many human tissues, and uniform enough to easily show any collateral damage. They discovered that the laser could etch living tissue in a precise manner with no thermal damage to the surrounding area.
While existing laser surgery methods had relied on heat and would damage surrounding areas in the process, using an ultraviolet laser to break up chemical bonds could dissolve a thin layer of tissue at a much lower temperature. Srinivasan named this new method ablative decomposition (APD).
Srinivasan, Wynne and Blum continued to run tests using the excimer laser and a conventional, green laser to etch organic matter. They found that while the green laser produced rough incisions, damaged by charring from the heat, the excimer laser produced clean, neat incisions. “That’s why it has this precision, because light can be focused,” Srinivasan explained.
In 1983, Srinivasan began to work with several ophthalmologists toward the possibility of applying APD to perform surgery on the cornea. Their efforts led to the procedure known today as LASIK surgery. LASIK has since revolutionized the field of vision correction, replacing risky, scalpel-based corneal procedures with a process that has become more reliable and comparably inexpensive. To date, more than 40 million people have taken advantage of this procedure, which reduces dependency on corrective lenses.
“The turkey experiment was in 1981, and you are now talking of millions of people being affected,” said Srinivasan. His work has led to the improvement of vision, increased personal productivity and greater economic opportunities worldwide.
Srinivasan has made many additional contributions to the development of photochemistry, including supervising numerous postdoctoral fellows and students throughout his career. He also has served as visiting professor at the City University of New York, Columbia Presbyterian Medical Center and Harvard Medical School. Following his retirement from IBM in 1990, Srinivasan founded UVTech Associates, a consulting company.
In recognition of their trailblazing innovations in the field of vision correction, Srinivasan and his co-inventors have received many honors, including the Prize for Industrial Applications of Physics in 2004, the National Medal of Technology and Innovation in 2012 and the Russ Prize in 2013. Srinivasan holds more than 20 U.S. patents and has published over 130 scientific papers.