Maybe it's just me, but I could almost swear that these glasses made my eyesight better! They are HUGE so if you have a small face or don't like that look, then these probably aren't for you. I got tons of compliments with them though and I don't normally wear large sunglasses. The lenses definitely change tint in different light although it is less noticeable than one would assume. It changes just the right amount.
The only problem with these glasses is that they are not very scratch resistant. They are built from this new superplastic called NXT, but they make the mistake of putting coatings on top of the base lens. The plastic itself may not be easy to scratch, but those filters and coatings are. Mine hit the pavement after a few months and got deep scratches right in the center of one of the lenses. Sure some of the coatings are nice, but I just want a scratch resistant lens.
Overall though I love the glasses! I just have to be more careful with my second pair. :)
4 stars because of the lack of scratch resistance.