Originally Posted by totalnewbie

Adhoc is a taiwanese company that makes RX sunglasses. I have one of their earlier generations (from almost 8/9 years ago) and the way they make theirs is they would have a cut out that they inserted and fuse the RX part and the non-RX perimeter. The benefit of that is the lens is essentially a one-piece construction with no sandwich layer to trap fog or rubbing. their later generations bypass that and have the RX as part of the curved lens. I was told that they use special calculation to account for the curvature of the lens, so no dizzling.

https://www.adhoceyewear.com/product...d1=27&kind2=44