There are different lens densities. I did not know this till we ordered glasses from Zeni. They offer the standard lens then for an additional cost I could get the higher density lens. Not that much higher in cost, at least from that source. They are also thinner and lighter than their standard lens (although with plastic lens that was not really a consideration with me anyway). Since going this route I do not have near as much problem with scratches, especially the type that one gets from cleaning dusty lens in improper conditions (shirt tail out in the field). As far as the scratch resistant coatings, the last glasses I got with that the coating wore off after a year or two and the glasses were terrible then where some of the coating remained and the other part not. That has been 10-15 years ago though so coatings may have gotten better since then. I quit paying for the scratch resistant coating after that experience.