For anyone interested, and kind of bringing back on track, with regards to Oakley Prescription Shades...
Oakley make the lenses themselves and they can only be ordered via an optician which stocks Oakely sunglasses e.g. Vision Express - although Sunglasses-Shop and similar can order them for you from a valid precription.
The lenses they use are the same Plutonite ones in the non-scripted glasses and can have the same colours and options (e.g. Iridium, Polarised etc.).
The way they do the prescription is a bit different though, mainly due to the shape of most Oakley lenses - ie wrap-around. Oakley use multi-focus progressive lens design, so a bit like vari-focal lenses, but rather than a changing prescription between the top and bottom for near/far sighted they apply it to the wrap-around nature so that the prescription you get looking straight through the centre of the lens is same as if you peek far to the edge of the lens.
The effect is bizzare and I can only compare it to wearing contact lenses, many times I have actually forgotten I have them on the effect is that sublime. All I can say is when I next need some (normal) glasses I will be looking at Oakley glasses frames and wanting Oakley Rx lenses for them.
Edit: Found a picture ....