I think this is an original idea - I've never seen this treatment before, and a quick google search doesn't turn up any. Even for those of us with fully functional eyes, this mod has value: I'd say 90%+ of the goggles I've seen on steampunks have stayed firmly on the forehead anyway.
EDIT Hey, featured! Awesome! Added an extra step to address some of the "Hey you can't see with those on" complaints.
Step 1: Materials and tools
LED (3.3v clear white. Diffused would probably be better. I used white because my goggles had a blue filter in them already, go with whatever color you like.)
Battery (CR2032 3V Lithium)
Battery Housing, for CR2032
Wax Paper (for diffusing. Probably not really necessary, but I figured it couldn't hurt.)
Tin Foil (for reflecting. See above.)
Bottle Cap (Vitamin water, in my case. Mine fit perfectly, if that hadn't been the case, I'm betting making it fit would have been the toughest part of this. As that will be custom to each set of goggles, I'll leave that as an exercise to the reader.
Hobby knife (you could almost certainly get away with just the hobby knife. I used the other tools because I had them.)
Things I should have used/will eventually use (not pictured)