I think, despite what you've explained, that prescription cycling sunglasses are a better option. If you were able to get prescription Ray-bans, then I would think that if you shop around the internet, you can find cycling sunglasses in a reasonable style to fit your prescription. Yes, they're costly, but if you take care of them, it's an investment that lasts for years. And yes, you may need to carry back-up glasses, but lots of people do that, and it's not hard to fit them in a jersey pocket.
The advantages outweigh the costs, in my mind. You can buy a much cheaper helmet, for starters, and if the helmet gets damaged or worn, it's easy to replace. You'll probably be much cooler, with better ventilation, than with the Air Attack (that visor doesn't appear to let much air get to the top half of your face). You may find you can wear the cycling shades other places, driving, to the beach or pool, etc. These are only some of the reasons why many cyclists who need glasses wear prescription cycling shades.