Maui Jim
I researched this thoroughly several years ago and came to the conclusion that it best to get prescription sunglasses made by the manufacturerer (same exact lens as the non-prescription). As far as I know, only three companies make a factory prescripition lens. Maui Jim, Serenghetti and Oakley. Other brands just use a tinted lens. IMHO the best factory prescription sunglasses made is Maui Jim. I've been using the high contrast bronze Flexon's for 2 years now. They are amazing! After using gas station glasses up until then, I just can't believe the difference. The downside is that they are expensive ($500). But since this is something I use everyday (OK I live in San Diego) it is well worth the cost. I tried the Serenghetti's and liked the MJ's much better. Keep in mind that MJ is only available in a polarized lens. So depending on what type of aircraft you are flying, there may be problems seeing EFIS displays without tilting your head to one side. For example, I heard that they work fine in the 737, but not in a King Air. The next best thing would be the Serenghetti's (non-polarized) especialy with the many positive responses posted.