Why lenses fog up and how to stop it!

7th February 2020

You’ve probably wondered why lenses mist up? And how to stop sunglasses fogging up? Fogging happens when water vapour (from exhaled breath and sweat from your forehead) cools down when it comes into contact with the lenses. The cold lenses cause a phase change as the warm vapor surrounds the lenses and turns the air into a liquid. Fogging also occurs when the lens is colder than the air surrounding the lens; this often happens if you move from outdoors to indoors. Or if you take your eyewear out of the relative warmth of a kitbag in cold air.

Fortunately, there are now some very good anti-fog products available, many specifically designed for close fitting sports sunglasses and ski goggles. We now have several options to choose from including these new OptiPlus Anti-Fog Wipes from lens care specialists Hilco. For just £5.95 you get a box of 30 individual anti-fog wipes (sachets). They’re long lasting and highly effective at fog prevention on all types of lenses including AR and hard coated. Use on sunglasses, ski and swimming goggles, spectacles, visors, sports eyewear and more. See them all in our anti-fog products section.