My biggest problem with masks is my glasses fogging up. I am at the end of my rope - I am looking into adding powered heating elements around the rims. There has to be some other way.
I used to have the same problem. My solution is that a use a foam tape and put that in the inside of the mask on the area around my nose. The uper area of the mask is air tight and therefore no fogged glases.
It looks like that but slimmer:
https://www.amazon.com/dp/B0000CBIFD
I hear your pain. And if use something with a stronger nose bridge like a KN95 or N95, it pushes your glasses out a small amount that make me slightly dizzy.
I had this problem pre-pandemic when I wanted to avoid glare but also not freeze my face off while walking to work. The solution was ski goggles-they isolate the lense from your breath.
Water vapor is a gas and is much smaller than the "leaks" of particles. A perfectly sealed filter (like an elastomeric mask with high fit factor) will still release a ton of H20.
EVIDENCE: The exhaust from PAPRS and viralhelmets.com has a ton of moisture.
With my cloth mask, I pull it up under my glasses, and let me glasses hold the seal. Just make sure your mask is big enough to still cover your face after you pull it up this high.
Where does the water vapor go? It condenses into droplets then skates back and forth along the bottom centimeter of plexiglass? That would be disgusting to look at. Or maybe it absorbs into the cloth hood/neck piece? That way when the user pulls it up off their head they get to squeegee their face with their own cold saliva. Sounds awesome!
Where on a lenses your eyes focus through matters (That why you need IPD to make glasses) Corrective lenses would be difficult to integrate so far from the eyes.
Most defog is just a soap film, and many divers including myself just use baby shampoo diluted in water. Store-bought defog is expensive and doesn't really work any better.
However, when diving you leave your defog wet (hence the baby shampoo so your eyes don't get irritated) after a quick dunk in water to rise off the excess. A coating that dries will be very different, although I am sure they sell it somewhere!
I've heard of people using Rain-X on their masks, but never tried that before. Maybe it'll work on glasses too!