CR39 will generally have no problem with chromatic aberration. Their optical properties are very close to real glass, meaning very good. They are also relatively scratch resistant.
Polycarbonate isn't very scratch resistant, but Zenni always scratch- coats their lenses. (It's very difficult to get un-scratch-coated polycarbonate lenses from anyone.) The best thing about polycarbonate is its impact resistance, so it's heavily used in sports glasses. I got fairly small glasses from Zenni with a -6.50 prescription (no astigmatism), and with their standard lenses, which are probably polycarbonate, I had very little trouble with chromatic aberration. Your stronger prescription, with a fairly large astigmatism, may have made the difference in aberration. My suggestion is to get small lenses (under 45 mm wide, maybe more like 40 mm) using CR39, and make sure they are scratch-coated. If you like the frames you got from Zenni, you could get the lenses replaced online fairly cheap. I used Wohl Optics (wohloptics.com), which charged me less than $30 for no-frills CR39 - no scratch- coating, nothing but lenses. Scratch coating and your higher prescription might cost more, but still much less than taking your frames to a local shop for lenses. There are several other places online that will refill your frames with CR39 lenses. Someone else will probably come along and name them and tell you how they worked out. I haven't tried anyone else online except Wohl. I don't think that lens polishing affects the chromatic aberration. I think it's mostly a function of how much of a prism your lenses are, meaning that it's worse if the difference in thickness is great between the center and the farthest edge of the lens. That's why smaller lenses are better. --~--~---------~--~----~------------~-------~--~----~ Check us out at the oft-updated http://www.glassyeyes.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 -~----------~----~----~----~------~----~------~--~---
