I looked at that site, and found that all those glasses seem to be polarized.
Physics says that one thing that polarization does is reduce reflections from objects. While that is good for your eyes, it does not help you in finding that aircraft which is heading right at you. That is the reason that polarized glasses are not recommended for flying.
Heinz
I bought some last year,
Link:
http://sunglasspolarized.net/
Avian 515 are on this link.
Edgar is the guys name.
Richard
www.craggyaero.com