Do you order the prescription Oakleys through an optician or buy direct from Oakley?
Generally if they sell Oakley frames they can send off for Oakley glazing. That said unless you want specifics they will push their own lenses as they can make them in-house and often they can do you better optic lenses cheaper.
are they supposed to work in the car? I thought car windscreen filtered too much UV for photochromic lenses to work (but I think there are some that are designed to work around this somehow)
No….and in bright sun during day -they don’t. But at night with modern bright lights they dim ever so slightly and take the edge off your vision to the point I’m not comfortable driving with them.
But more that if I walk into a building from bright sun into the building – they remain dark for an annoyingly long time