I bought Z clear when I first started wearing a mask and have mostly loved the product. I usually have to reapply once every couple weeks or so and the sunglasses stay clear when I’m wearing the mask and glasses. But occasionally, if I put the glasses on too soon after I apply the spray and wipe clean, moisture will form on the inside of the glasses. It’s better than fog, but still annoying.
best recommendation, apply the spray, let it sit on glasses until it dries, 5-10 minutes, then wipe clean. Let them sit for another 10-20 minutes and you should be good.