Davo,

I've been wearing perscription sunglasses on the water for a while now. They are metal frames of reasonable quality, and the lenses are in there pretty tight. I was assured by the optometrist that they wouldn't fall out, and they loctited the screws into the frames.

I had some lenses 'retro-fitted' to a pair of plastic sunnies once, but the plastic flexed easily and I lost a lense (yep, in the water).

If and when I get another pair made, I'll get polaroid lenses for glare (apparently no good for the racer types who need to read LCD screens), and if possible those lenses where the tint changes as you go from dark to bright light. This is mainly for winter when it can get dark on a cloudy day. Nothing worse than trying to see through dark sunglasses and rain on a cloudy day.

There was another thread on the subject of sunnies in this forum a while back too.

cheers for the replies,
Yeah i was told by my eye doctor that lavas are probably a bit curved but they can make lenses for anything but if they are too curved your vision will distort heaps. Maybe it's more if you've got really thick lenses like me (-6 in one eye). Interesting about the metal frames, i would have thought the plastic would be more wave tough, maybe i can super glue my lenses into my plastic sunnies!