Help prevent fog build up with oakley liquid oo zero fog. When applied to the inside surface of an eyewear lens, it helps to improve its fog resistance. Regular application of anti-fog spray can greatly improve the fog resistance of lenses. If eyewear has prescription inserts, they may be prone to fogging due to being close to the eye. It is recommended to apply the anti-fog solution on eyewear and prescription insert lenses prior to first use. 1. Spray the entire front and back side of the lenses 2. Rub the lenses with a tissue until completely dry 3. Re-apply as needed to keep fog away. Do not use abrasive cleaners or solvents such as ammonia. These may scratch or weaken the lens. If the lens is scratched or fractured, replace the lens.