I work as an Optician for a College of Optometry. We have been using Trivex material for several years now. The optics are great with an ABBE value of 43 versus Poly's ABBE of 31. It is greatly superior to Poly. The price has also come down quite a bit than when it was first introduced. We only charge $15.00 more for Trivex than we do for CR-39 or Poly.