How Cold Light Was Introduced to Arthroscopy

In 1954, in a landmark publication, H. H. Hopkins reported that images could be transmitted through glass fibers. This stimulated many investigations and, in 1957, B. Hirschowitz at the University of Michigan, succeeded in constructing a much-needed flexible gastroscope using optic glass fibers. Coating of the fibers by glass of lower refractive index was the next major step forward. Optical fibers were thus insulated and the accuracy of the transmitted image and the light transmission capacity of the fibers were enhanced. Working with American Cystoscope Makers Inc, L. Curtiss and H. Hett were the first to use glass fibers for illumination in an endoscope, producing a flexible ureteroscope in 1960. The light transmitted by the fibers was named “cold light” because it produced little heat, but the term had been used before for other types of illumination. The first arthroscope equipped with cold light was Watanabe’s arthroscope No. 22 built by Tsunekichi Fukuyo in 1967. However, Watanabe was not satisfied with the new instrument and he still preferred the conventionally illuminated No. 21 arthroscope with the offset tungsten bulb at his tip. After R. W. Jackson reintroduced the technique to North America, most American pioneers used this conventionally illuminated arthroscope as well. But the early European arthroscopists had cold light instruments made by the German manufacturers R. Wolf and K. Storz since 1969. These rod-lens cold light instruments expanded in all markets during the following decade.