Those of us who wear glasses or sunglasses have to solve another problem: wearing a mask causes glasses to fog up. How do we prevent this? Ask the doctors who regularly wear glasses and masks.
The fog is caused by your warm breath hitting colder glasses. Doctors can share a number of ways they prevent warm breath from clouding their vision.
Make sure your mask is tight across the top. If you have a medical mask with a built-in bendable strip, be sure to mold it to your nose. The mask straps should be tight, so the mask does not gap across your face.
Doctors have other techniques for sealing the tops of their masks. Some use medical tape across the top of the mask to prevent air from escaping and hitting their glasses. Others pull the mask up high so their glasses sit on the mask and seal air in.
The soap and water trick. Another technique some doctors swear by is washing their glasses in soapy water and letting them dry in the air. There is some science behind this. Soap is a surfactant—a substance that reduces the surface tension of a liquid—creating a thin film between the lens and your breath. In fact, a study published in 2011 in the Annals of the Royal College of Surgeons of England vouched for the effectiveness of this technique.
Commercial anti-fogging products. There are many different products on the market. Just be sure the product you choose won’t damage any coatings on your lenses.