Why lenses mist up – and how to prevent it

22nd November 2021

Autumn and Winter is the time of year (here in the UK) that eyewear lenses are more prone to misting up. You take your sports eyewear out of the kit bag, put them on your face and instantly they mist up. It’s the same when you get into the car in the morning, put your sunglasses on that have been left in the car overnight and again they mist up. So what’s happening? It’s the interaction between the cold lenses and your (relatively) warm face. The cold lenses cause a phase change as the warmed-up air behind the lens (from the heat of your face) turns the air into a liquid – condensation on the lenses. You’ll no doubt have experienced this many times moving from outdoors to indoors and when wearing a face mask (your warm breadth is pushed up behind the colder lenses of your spectacles). It’s more likely to happen on close fitting wrap-around sports eyewear as the warm air behind the lens is “trapped”.

Fortunately, there are now some very good anti-fog products available, many specifically designed for close fitting sports sunglasses and ski goggles. We have several options to choose including both sprays and wipes. Most double-up as a very good lens cleaner too. Use on sunglasses, ski and swimming goggles, spectacles, visors, sports eyewear and more. See them all in our anti-fog products section.