I & a lot of other middle aged sailors wear perscription glasses. I hate to wear contacts just so I can wear sunglasses. So I bought a pair of "Polar Eyes" wrap around sunglasses that are designed to fit over your existing glasses. They are dark, obviously polarized, are relativley cheap at $25 & can be bought at any Sams Club. I also like the wrap around feature that stops glare from getting in from around the frames at the corners. I have heard of sailors actually getting burned cornias from too much glare off the water in combination with wind. So no matter what the cost, its worth protecting your vision. When you don't strain from squinting you see better & I don't tire out as easily when I can actually see what's in front of me. My 2 c.