I wore sunglasses with my mask the other day when I went into the grocery store and within minutes, t hey were completely fogged-up. So, I found some info from HuffPost to help prevent the fog. Here are four quick tips that might help...
1. Make sure your mask is as tight as possible across the top. Most of the time, the issue is warm air escaping through the top of the mask, so try that first.
2. Wash your lenses with soapy water. The fogging-up also happens to surgeons when they wear glasses with medical masks. Using the soapy water is one way they deal with it and a study in 2011 found it works pretty well.
3. Add a folded tissue inside the top of your mask. If you fold it a few times and put it right between your mask and the bridge of your nose, it'll help to absorb the moisture and should lower the amount of condensation that ends up on your lenses.
4. Fold the very top of the mask inward. It only works with masks that don't have a form-fitting metal piece for your nose. It creates extra space for your breath to escape before it hits your glasses. The drawback is there's less of a seal that way, so it has its pros and cons. Personally, I want that seal to be as tight as possible so it's safer.