Doesn't hide too much light, but lets in just enough so no squinting. I use these glasses mostly for biking and they stay in place and ventilate well, except if you stop and they fog up a bit, but as soon as you get going again it disappears. I never have to worry about them and the really nice thing is that the ends where they tuck behind your ear it never pulls your hair like other glasses, which is a win. I bought another pair only after this annoying little untrained dog chewed them up.