On Thu, 21 Oct 2004 21:24:00 GMT, "Doug"
wrote:
I had one
pair that I had to discard when flying small aircraft and the curved
Plexiglas windscreen showed all the heat stress lines from forming the
curves in color when using those polarized glasses. Higher quality aviation
polarized sunglasses did not have the problem.
======================

Interesting issue. I've always taken the ability to see stress
paterns as a sign of quality in a polarized lens but I can see where
it would be a problem as you describe.