[huxley]

Decent point, but most people familiar with metric would work with smaller units than metres and for those unfamiliar with metric, describing it as a billionth of a yard would still sound like a pretty peculiar.

I think describing it as a minute fraction of an inch or centimetre would still be pretty accessible without having to get people to visualize a nanometre.

[vt240]

I only watch the US cable news. How many football fields thick is the lens? 1.823×10^-9 NFL football fields.

[goldenkey]

Lay people dont understand exponents. Just say its small.../s

[vt240]

three points was enough to laugh for at least an hour. Good enough :-) No?

[euyyn]

Or, as we're talking of lenses, fraction of a milimeter.