Had to have mine de-polarized - my sunglasses are my Rx, they remade them without charging (which was good since I bought Maui Jims and they are a bit pricey ! ) - the optician said she knew about rainbows and shadows in windows, but didn't think about my helmet face shield - even tho the glasses I bought specifically to fit in my helmet - brought it in to find frames)
Couldn't see through my face sheild without shadows from the polarization - it was a very weird experience. There were shadows in my windshield too, but I don't actually look thru it....but very strange.
Becky