The lenses have been covered with our Anti-fog coating, a lens treatment that will make your lenses more resistant against fogging up. Your lenses fog because of temperature differences and the level of moisture in the air, meaning when warm or moist air hits the cool surface of the lenses, fog can occur. This can be the result of your engaging in intense activities or simply due to changes in weather conditions. But with these anti-fog coated lenses, you get lenses that are highly resistant against fog, ensuring you a clearer vision even under high-performance activities.