I read about using yellow tinted lenses for running in the early morning or late evening. These are just amazing. When I run in fog or gloom it almost lights up the trail, making everything crisp and clear. Even better, I've been cycling a lot of miles in hard, foggy rain wearing this bad boys. Wow!! I did 42mi yesterday with a friend wearing clear glasses. When I let him try these on, he asked for a link to order his own! For dark or inclement conditions while working out, you need these!!