Can I add another little point from the UK? In our
magazine 'Sailplane and Gliding' a couple of months
ago, I read that polarising lenses are not recommended.
Apart from the problems already mentioned (canopy
stresses, LCD readability etc), apparently polarising
glasses also eliminate wing glint (so you don't see
that other glider so soon) and wires (UK pilots get
to do field landings quite often, thanks to the weak
soaring conditions we often have)