The glasses wearers among us have most likely come across a new challenge in the past couple of months: when you strap on your cloth face mask, your glasses instantly fog up. But fear not, there are a few tricks and techniques you can do to avoid this mildly infuriating state.
One technique comes from two surgeons in the UK who wrote a paper in the Annals of the Royal College of Surgeons of England in 2011 explaining how doctors keep their glasses from fogging up while performing surgery in the operating theater. Best of all, it just requires soap and water.
“Immediately before wearing a face mask, wash the spectacles with soapy water and shake off the excess. Then, let the spectacles air dry or gently dry off the lenses with a soft tissue before putting them back on,” Sheraz Shafi Malik and Shahbaz Shafi Malik write in their paper.
“Now the spectacle lenses should not mist up when the face mask is worn.”
They explain that the misting occurs from the warm water vapor in the breath condensing on the cooler surface of the lens. However, if the glasses are freshly washed with soapy water, then the lens will be covered by a thin layer of surfactant – a substance that reduces water’s surface tension. This stops the condensing water vapor from forming large droplets on the lens, which can obscure vision and help to disperse the water molecules evenly into a transparent layer.
You can use any type of soapy surfactant to achieve this, but dish soap is said to be one of the most effective. It’s also possible to buy an anti-fog spray, which swimmers and scuba divers often use to stop their goggles from fogging up. Some swimmers even rub a small amount of spit on their goggles as the liquid helps to deter further condensation, although it’s unclear how effective (or pleasant) this technique is with glasses and a face mask.
Another paper in the American Society of Plastic Surgeons recommended sticking tape on the bridge of the nose, which the surgeons claim helps act as a barrier between the top of the mask and the glasses.
If you use face masks that tie around the back of the head with a cord, as opposed to the design of masks that loop around your ears, you can also try another technique. Reported in the Annals of the Royal College of Surgeons of England, surgeons DJ Jordan and R Pritchard-Jones recommend tying the face mask's cords with a bottom tie above the ear and the top tie below the ear in cross-cross fashion (there are images in the paper if you're confused).
“This approach allows a closer seal over the nose and along the infraorbital ridge, stopping venting at the superior part of the facemask, and forms two lateral ‘vents’, allowing exhaled air to escape away,” they write.
If none of these techniques suffice, then hold tight. Warming springtime weather should help to discourage your lens fogging up as outdoor temperatures and your lens will be closer to the temperature of your breath, making condensation less likely.