I'm looking for polarized prescription sunglasses, ideally with interchangeable lenses. I fly fish, paddle, sail, cycle, and ski, and I have a big melon, so smaller-fitting frames won't work. Am I asking for too much in a single pair of sunglasses?
One pair should meet your needs. After all, glasses are meant to protect your eyes, reduce UV rays, and cut glare. That’s true whether you're skiing, biking, or fishing.
You can buy the Oakley Fast Jacket with two interchangeable lenses made to your prescription. They've got adjustable nose pads, and a new mechanism that makes changing lenses quick and relatively easy. The style is somewhat cycling centric, but they won't look out of place fishing or skiing. You can order them with polarized lenses or even super-tough polycarbonate lenses. They start at $220.
For something really hot looking, check out the Rudy Project Rydon ($175). They also fit medium to large heads and, of course, come with interchangeable lenses.
Another interesting choice is the Julbo Bivouac ($120). These have magnetized side shields that snap on and off quickly, which could come in handy for skiing.
Several websites offer of sports glasses with prescription lenses. Take a look at Sportrx.com, or Sporteyes.com.