In reply to d80f0u:
I've gone down the Julbo route and have (moderate/strong) shortsighted prescription. Optician created right fuss when i said i had my own frames and that none of hers were good enough... Then i showed them and they had to agree.
However, a word of caution for anyone getting the original lenses replaced - the leather covers won't fit without modifying the fixings, as the edge thickness of the glass has increased.
This shouldn't be a problem if you're long sighted.