If you are having issues with foggy glasses, soap and water may do the trick. According to research published in the Annals of the Royal College of Surgeons of England in 2011, doctors who washed their glasses with soapy water, without rinsing, and let them air dry prior to wearing a face mask experienced reduced fogging.
Washing glasses with soapy water “leaves behind a thin surfactant film that reduces this surface tension and causes the water molecules to spread out evenly into a transparent layer,” the study said. “This ‘surfactant effect’ is widely utilized to prevent misting of surfaces in many everyday situations.”
Folding a tissue and placing it on the bridge of your nose and underneath your glasses also helps reduce condensation as the tissue will absorb the moisture from your breath. – from an article in the LA Times
Other Ideas from VersantHealth:
Put a tissue inside the top of the mask. If you fold a tissue horizontally and put it between your face and the top of your mask—so it sits over the bridge of your nose— the moisture from your breath will be absorbed by the tissue instead of hitting your glasses.
Use a defogging spray. There are a number available for purchase online. Snorkelers and competitive swimmers often use these sprays to prevent foggy goggles. But remember: these sprays contain chemicals, so check out the reviews carefully before buying them. It’s important not to cause irritation that could impact your eyes and your vision.
Jonathan Hill, Doctor of Optometry 