When it comes to triathlon eyewear, it's about more than just optics and protection from the sun. Triathlon sunglasses have to deal with variable conditions on and off the bike. They have to fit well to avoid irritation and to make sure they stay secure on your head. When cycling, the glasses have to fit well to protect against wind and all kinds of summer insects. Almost all well-known sports eyewear suppliers pay attention to reliable UV protection and lens tints for every possible condition.