Hmm, I tried following your above description to get the shader to be just plain glass for the sunglasses but I must have messed up somewhere, it rendered black. Do I need to change the Refract color to black?  And, knowing me, I'll try this as a water shader at some point......

"A lonely climber walks a tightrope to where dreams are born and never die!" - Billy Thorpe, song: Edge of Madness, album: East of Eden's Gate

Weapons of choice:

Poser Pro 2012, SR2, Paintshop Pro 8