HALL OF FAME / inventor profile

Rangaswamy Srinivasan
Born Feb 28 1929

Far Ultraviolet Surgical and Dental Procedures
Patent Number(s) 4,784,135

Inducted 2002

In 1981, Rangaswamy Srinivasan discovered that an ultraviolet excimer laser could etch living tissue in a precise manner with no thermal damage to the surrounding area. He named the phenomenon Ablative Photodecomposition (APD)

Invention Impact

Srinivasan and his co-inventors ran tests using the excimer laser and a conventional, green laser to etch organic matter. They discovered that while the green laser produced rough incisions, damaged by charring from the heat, the excimer laser produced clean, neat incisions. In 1983, Srinivasan collaborated with an ophthalmic surgeon to develop APD to etch the cornea. It resulted in a procedure to correct vision known today as LASIK surgery. Since the introduction of LASIK, millions of people have taken advantage of this procedure that reduces dependency on corrective lenses.

Inventor Bio

Srinivasan spent 30 years at IBM’s T.J. Watson Research Center. Throughout his career, he has received many honors and awards and has been granted 21 U.S. patents. He received both bachelor’s and master’s degrees in science from the University of Madras, India, in 1949 and 1950, and earned a doctorate in physical chemistry at the University of Southern California in 1956. Today, he consults on lasers and laser applications.

© 2002 National Inventors Hall of Fame