craftgrrl | mask dilemma

I'm going to a formal masks-required masquerade ball and I need to come up with a way to wear a mask that somehow accommodates my glasses. I can't wear contact lenses and there's no way I can go without them. I'm not having any luck in costume shops as I expected, so I'm thinking I will have to make my own...but I don't really know where to start. I've been searching but am not really coming up with anything that would work...any ideas? Thanks in advance!