I wear glasses for vision. When I got them I thought about getting a pair of prescription sunglasses and the optomitrist said that I could get any frame and swap the normal lenses for prescription. That was going to be very expensive so I just got the Transition lenses on my normal vision glasses. It's not as dark as actual sunglasses, but it really helps with sunglare and it means that I don't loose any glasses coz I'm not swapping them around all the time.
I am looking forward to buying a nice pair of sunglasses, but I'll wait until I can afford to get contact lenses.