Kelvin Continuous Curve Contact Lens

Historical Significance: The proprietor of Kelvin Lenses Ltd, R.K. Watson, (1911-1974) designed a lens with a conical transition (developing the 'Feincone' idea of Feinbloom in the USA), making it more of a comfortable lens than the Zeiss. An elaborate manufacturing set-up using metal moulds meant that in 1947-8 the company could sell more than 120 fitting sets containing fifty lenses in each set. Kelvin Ltd introduced contact lenses to Holland, Belgium and parts of Scandinavia. From its factory in Denton it became the UK's largest manufacturer of corneal lenses because its moulding techniques were more consistent than those to be found in factories using lathes. Watson was an optometrist setting up his practice in Cheshire when he was 21. He began fitting contact lenses in 1945. Despite post-war difficulties, he set up a workshop with a small group of friends making scleral lenses and this became Kelvin Lenses Ltd. In 1946 he spent several months in the US. He was impressed by Feinbloom whose lens design was based on a conical section resting tangentially on the globe and was more comfortable than the Zeiss lenses but he decided that a combination of the two might prove even better. He designed a conical transition 5 mm wide and developed a manufacturing process using a metal mould with several parts. See Watson RK The Kelvin contact lens. Optician. 1947 Oct 3;114(2948):228-30: Watson RK. 'Twenty Years After - The Story of Moulded Contact Lenses', The Contact Lens J., 1965.