It seems very unlikely that Zenni offers CR39 at all. Their standard lens may not be polycarbonate, though. There was a discussion about this here not too long ago, and the index of true polycarbonate is not the same as the index that Zenni lists.Since I haven't had trouble with chromatic aberration on high-prescription standard lenses from Zenni, I myself think it's likely that it's not actually polycarbonate.
The only two materials used in lenses, as far as I know, are glass and plastic. There just happen to be a lot of different kinds of plastic. Not all plastic even has anything to do with petroleum. --~--~---------~--~----~------------~-------~--~----~ Check us out at the oft-updated http://glassyeyes.blogspot.com! You received this message because you are subscribed to the Google Groups "GlassyEyes" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/glassyeyes?hl=en -~----------~----~----~----~------~----~------~--~---
