When you're buying sunglasses, there are a few things to keep in mind whether you plan to spend $10 or $1,000. First, look for gray or brown lenses to cut down on color distortion. Then, consider how much coverage the lenses provide. Wraparound lenses can block up to 5 percent more rays. And check to make sure they are listed as having "UV 400 protection—this means the lenses block up to 400 nanometers of UV light.
You'll also want sunglasses that promise some kind of impact resistance, especially if you plan to shell out for designer frames. They won't do you any good if they can't withstand your activity level or a trip to the bottom of your beach bag.