I don't think he learned anything. It's more "what did I learn so that I could go blind in space and survive ok?"
http://www.ted.com/talks/chris_hadfield_what_i_learned_from_going_blind_in_space#t-899005
http://www.ted.com/talks/chris_hadfield_what_i_learned_from_going_blind_in_space#t-899005