I wear glasses and wear any dust mask (I'm in the trade so use a lot) and don't have a problem with my glasses misting up. When you fit the mask around your face you must pinch the metal band that fits around the noise until the mask fits without leaking otherwise your glasses will mist up.
I know a lot of people have this problem and I used to until I made sure the mask fit my face.
.................... the AirAce mask is best for me. I used to get all steamed up with my glasses, but thios covers nose and mouth with a good seal and can wear it for hours. Looks like Darth Vader, but very comfortable
Malcolm
I use this. http://www.arco.co.uk/products/168600?s=1
if I'm using contact adhesives I put in a gas filter and can't detect a thing. I've got a beard but it still gives a good seal and passed the face fit test our safety rep does
Just recently purchased the 3M 7500 model I use the 7502 medium fit, with 3065 particulate filter fitted.
If you breath using your mouth not your nose I never have a problem with my glasses steaming up. But that me can speak for anyone else.
Just watch out for the fakes on Ebay.