Editor,—It seems a surprising omission from the Waldocks' recent commentary1 on the future of microsurgical instrumentation not to have mentioned contamination with specific reference to transmissible spongiform encephalopathies (TSE).

It is known that prion protein is not reliably destroyed by most disinfection or sterilisation procedures, including autoclaving at a temperature as high as 138°C for an hour.2 Although more effective methods, such as exposure to combinations of alkali and heat, are being developed3 they may require instruments to be particularly durable. Also fine, and particularly, toothed instruments require thorough cleaning before sterilisation by current procedures, to avoid retention of tissue.

Although there is no clear evidence of the transmission of TSE from one patient to another by ophthalmic surgery other than through corneal transplantation,4 the only extant Department of …