Eliminating fog is the name of the game! The cause of fogging is when the inside of your goggles are a lot warmer than the outside, which is why air all our goggles have vents on the top and bottom of the frame that help keep the airflow circulating. On top of that all our lenses are double layered and made with anti-fogging coating built into the lens itself. This means the coating is permanent and cannot be wiped away after cleaning unlike most of the anti fog coatings other companies use. Another important thing to remember is that if your face mask is tucked under your goggles the hot air trapped in your face mask is going to make its way upward and will add to the heat inside your goggles, that is no bueno for any goggles.