I bought my last pair of glasses at the Walmart vision center and chose the nikon lenses with the protective coatings that darken in sunlight. They have been so good for me. Unlike other lenses that darken in sunlight when you're outside but not so much when your in your car or whatever, these darken when you're in your car. I never have to worry about finding my sunglasses, where my husband who has the other kind of darkening lenses has to use those kind of sunglasses that can be worn over his regular glasses. And his glasses never get dark enough to really use them as sunglasses when he's outside. My nikons do, though. And they were only a couple of dollars more with my prescription than the other brand. My husband says he's sold and is going to buy the nikons next time he gets glasses and I'm so happy with mine I doubt I'll ever buy anything else. I can even ride my Honda Reflex with these glasses and never get bothered by the sunlight or the glare off the road.