After dropping my $100 "aviator" sunglasses and shattering a lense (and
couldn't find replacement lenses), I turned to my old friend, Amazon.
Here's what I settled on: Tifosi Sunglasses
http://www.amazon.com/gp/product/B00EKERBU4/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1.

At a quarter the price, these are the best sunglasses I've ever had, and
replacement lenses are also available on Amazon. Just thought I'd share.
--
Dan Marotta