Ah, Michael's. I love that place, particularly around the holidays when they break out those Halloween and Christmas Town displays... most of it is overpriced, but some of it works really well for minis. :3
Anyway, I find the best way of making spectacles is to forget the frame and just concentrate on the glass - maybe try putting small circular discs of paper or Green Stuff on either side of his nose. Painting them well can make them look like glass. You could try to make them look semi-clear, painting the flesh detail behind them magnified slightly, with a slash of white glare, but I've found its far easier to just paint them dark as if they're shades and caught the sun and are glinting.