The Best Pilot Sunglasses
As someone in the business of Aviation Medicine, Hawk's post is an excellent summary of the current recommendations. The original work was done by an Australian Opthalmologist, John Colvin, when he worked at NASA. The results of the studies are published in the journals Aerospace Medicine and Aviation Space and Environmental Medicine. Do a medline search.
Summary of specifications: Large thin titanium frames for field of view
Polycarbonate lenses
Neutral density Gray Green tint
15% transmission of light