www.seaspecs.com/They have a 3 for 2 deal so you get 3 pairs for $100
You can get basically the same glasses from yachting shops for $40.
Don't buy expensive ones. They scratch just as easily as the cheap ones.
RainX helps repel water a little. You're rarely sailing fast enough for wind to blow the water drops off. The best thing is to clean the lenses well as possible. That stops water sticking and reduces fogging. Washing the glasses in warm water with dish washing detergent works quite well to de-grease the lenses.
The most important thing is to put your sunscreen on early so it dries properly and clear your eyebrows of excess. The excess suncreen runs into your eyes and onto your lenses so you can't see, you have sore eyes, and you can't rub them.
Gath helmets are ok but the ear covers make the wind noise really loud.
) the helmet band behind lug holes (ears)will sometimes push down on the arms and lift the bridge up on nose. For none prescription, no problem, but if prescription multi lenses its a tad awkward 
) as unlike everyone else I can't wear sunnies under my Gath - the arms do press into my temples. I've tried some sunnies that just have straps, no arms, but they tend to rise up when I look down and obscure my vision. 
