I have a pair of these. When using gel earseals, there is absolutely no difference to sound transmission compared with using contacts / no glasses.
http://www.silhouette.com/en/product...0351/index.asp
Whilst not cheap, they are the most comfortable glasses I have ever had. There are lots of shape and style variants, and you can get a discrete sunglasses clip ( I have not used it flying yet).
Even worth buying if a non-aviator.
J