Why throw money overboard I have always made do with regular polarized sunglasses. The best ones I had to date was the cheap "Solarshield" ones ment to go on top of other prescription glasses. They really shielded your eyes from sun and water and had really eccentric looks
To keep the water off there are third party products help with that. I have never used them, but perhaps I should?

When I buy expensive sunglasses, they are either stolen or otherwise lost The cheap ones, like the Solarshield, lasted for several years, until my four year old grabbed at them for support while on a monohull.. Curse of the monos I guess.

They dont sell solarshields here in Norway, so now I am browsing through e-bay to find the right model from somebody who ships to Norway.