[pnacze199204]

It is believed that if two objects slide over each other or even touch each other there's always a loss of material. I would like to ask then a question about diamond knives used in eye surgery, whose blade thickness is often 50-200 nm. Some manufacturers claim that replacement of such a knife is recommended after 10.000 incisions. So how is it possible that such a blade is able to serve that long when 50 nm is really very little?

[Borek]

It is believed

By whom?

But it actually doesn't matter what is "believed", what matters is what tests say. If they falsify "beliefs" it is time to change the opinion.

[pnacze199204]

I read about it in some book and just quoted the statement.