It is worth stating that I am supplied glasses by Costa Sunglasses and as such that is what I wear. Optical clarity is very important and that is where a lot of development cost goes for companies like Smith, Costa and Maui Jim among others. 

Purchasing from a fishing oriented brand is going to yield better results than from a generic company such as Ray Ban, Oakely etc as Lens tint and shape will Optimised for what we do.

My preference is for Glass Lenses as the additional scratch resistance is incredible, however you need to be more aware of breakages due to shock impact (dropping them, having a swivel hit the lens etc).  I have a pair of Prescription lenses from Costa which are plastic lens, and they require lots of care to make sure they don't scratch. I keep a very damp clean Chamois in the bridge to knock the salt off, then I use a Lens wipe after that.

When purchasing your glasses for fishing, you ideally want a pair with lenses that hug the profile of your face, this stops light getting behind the lens and reflecting in your eyes. Obviously, wearing a hat at all times will heap massively with this also. You may find a pair that looks better, but fishing glasses should be optimised for fishing, not looks.

Deciding what tint or Lens colour to buy is equally important. I have amber lenses for early morning or river fishing, and Blue mirror lenses for offshore work on a clear day. Grey Lens or green mirror can be a good option to cover most bases well. Costa has a great website to help you choose a lens color and shape.

Hope that helps.

I took them into the place that sold them to me and they said sweating, sunscreen, grass and a few other things cause that "damage" to the coating. Given they're designed for outdoor wear it's a bit ludicrous.

Anyway, I now have a pair of glass polarised Spotters (with the blue reflective lens) and really like them. Got them in a sale from Australia.

I prefer styles with a bit of a wraparound design for eye/skin protection and practicality of keeping our rays from the side for vision.

I also use a comfortable neoprene lanyard which means they almost never get put down in the boat, so never have a chance to get scratched.

Got old and have to wear prescription polarised now or clip ons.

Used and lost heaps. My best pair were Vuarnet glass - just magic. Put them in shirt pocket and leaned over the side.....glug, glug, bye bye $350.

Also have still got Spotters lenses but in a cruddy frame.

One lesson I learned was never to put a pair in a dishwasher!

Have gone through literally dozens of brands over the years as I wear them for eye protection all day on the building site .... not just on sunny days on the boat or driving.

Weirdly enough have gone full circle and currently back to Oakley... Double edge this time. They just fit the shape of my face, are crystal clear, extremely comfortable   and last for bloody ages. I guess its human nature to try new shapes and styles as years go by... but im probably going to get another pair ( 3rd in 4 years) of same style they have been that good. Have heard good things about Maui Jims. Might be better for boating.