The Giro Index OTG Goggles are designed for skiers or riders who wear glasses. Designed to not only fit over your glasses but also the cylindrical lens provide the most clarity for your glasses. Cylindrical lenses are really important for Over The Glass (OTG) goggles. Unlike, spherical lenses that are shaped like the curve of the eye which provide the best optical clarity for those without glasses or contacts, Cylindrical provide the best optics for those with glasses by cutting back on distortion of two lenses. Every Giro goggle lens features our anti-fog coating to keep your vision and riding experience on point. Vents cut into the lenses above the gasket line allow warm air to escape and keep your goggle from fogging. Spectral Band technology reacts to protect your eyes from blinding glare.