EFHSS Questions and Answers - Question Q00200

has anyone experienced whether steam sterilization has affected the lifespan of telescopes. particularly arthroscopy and urology scopes
thanks

Dear Geraldine,

All manufacturers of telescopes using gold welding to seal the telescope at the distal tip for the window, can guarantee you more than 1500 cycles of autoclave. This technique originally designed to be used in spacecrafts, permits important temperature fluctuations in a short time ie. A spacecraft circles around the world in something like 45 minutes. During this time it heats up to +250°C on the sunny side and cools down to -250°C on the dark side of the earth and still the welding stays unaffected. Some manufacturers are still using industrial glues (cement)to fix the distal lens. Cement saturates itself with moisture between 0.5 and 5 % of its weight.In other words this means that in the best case the 100% saturation will be obtained after 200 cycles and in the worst case already after 20 cycles. The degree of saturation after each cycle can vary between 0.5 and 5 % even for the same cement. Therefore these manufacturers have no certitude about the lifetime of the telescope. In addition, some companies have incorporated a drying element in the body of the telescope in order to absorb any residual moisture which could have been trapped in the telescope and accounting for early corrosion and leakage of the telescope. Be careful: some companies state that their telescopes are autoclavables although they are using glue. When moisture comes into the lens system they always try to convince the customer that they dropped it and that lenses are broken. This can easily be distinguished by using a watchmaker loupe to inspect the telescope.

Dr. Ives Verheyleweghen