While the average “gas-station sunnies” are better than nothing, if performance is what you seek, I present you the Burnet by Kaenon.
For anyone having fun in the sun all day long, sunglasses are a MUST. Not only do they protect your irreplaceable set of eyes from harmful UV rays and glancing blows, they make “seeing” the wind easier, a necessary skill for any racer.
Kaenon glasses are created with a special SR-91 lens that is lightweight and shatter-resistant like polycarbonate, yet boasts the minimal distortion only found in glass lenses up to this point.
The polarized lenses are available in different tints as explained here, but overall it breaks down like this:
Gray for crystal blue water - great for Miami
Copper for color enhancement in dark water or lower light situations - perfect for the Chesapeake.
Brown for a combination of both worlds - for the jet setter
The frames are designed to contour the face in an athletic fit; better protecting your investment from flying off and into the drink.
I have a pair myself and don't leave home without them. Kaenon's have been trusted by sailors all over the world for their classy looks and unique lenses.