ZOLTAN A N.wrote a review of Costa Hammerhead 580G Sunglasses - Polarized on May 14, 2012
The 580 are top of the class lenses but the frame is a bit bulky. Glass lenses are becoming considerably lighter these days but this one still weighty on the nose (maybe thats only my problem). I am still not sure if I could take it for a whole day though you can get used to it.
Be aware of the size (medium to large). Hammerhead differs from Swordfish only with the prolonged shape at the temple otherwise these two glasses are of the same size.
I believe my face is standard. From Costa I may need the large size frame. I keep the Swordfish. Even with sunglasses you could be better off by trying on before you order. (I use glasses only for reading.)
Best use for open water conditions. For driving the copper lens could be a better choice.
I bought the Swordfish for fly fishing. No glare whatsoever. Great look.