The ANS for eye protection is Z87.1, which gives a specific impact resistance rating to the eyewear. This standard is commonly used for shop glasses, shooting glasses, and many other examples of protective eyewear.
Hmmm, yeah I think you guys must be spot on with the ANSI stuff. Now it just makes me wonder if the lens is anything special ... or just a regular lens with the specific ANSI etching in order to be used and meet the safety lens market requirements. I think it is just a VR28 lens - maybe I will need to do some more comparisons from my collection to confirm. It just came through DE/Discontinued stock, here are pics of the lens: