I bought these sunglasses because my old sunglasses fog up as I climb up singletrack. They have been excellent; designed to allow air to flow around the lens so they don't fog up when you really need to see the singletrack ahead when climbing. The only problem is if you sweat a lot on a long climb and it is a calm day, they will fog up slightly but I suspect any other pair of sunglasses will be worse. I bought the oldest model available due to my budget so great value for money. Also, they were available from my go to supplier of biking gear so they were delivered next business day which makes my life easy now that I work from home (and mountain bike from home) regularly:)
Ink