Remove one lens out of the sunglass and place it in front of the other lens in the exact same position as the lens that is in the sunglass. You should be able to see clearly through both lenses.

Then, rotate one of the lenses 90 degrees while looking through the lenses. As you rotate the lens 90 degrees, the lens will ?black out?? and you should not be able to see through it any more. (This is because the polarization axis which were running horizontally, much like a Venetian blind, are being crossed over each other, effectively blocking out all light) If you can?t see through the lens as it ?blacks out?? the lenses are polarized. If nothing happens, and you can still see through the lenses.. they are not polarized.


Don't take your glasses apart if you do not have to. If you already have polarized clip ons or non-prescription polarized sun glasses, the 90 degree trick will work. In stores I do this with two pairs of glassed from the shelf to verify that they really are polarized. BTW UV blocking does not mean polarized. And polarized does not necessarily mean UV blocking.