|Index ||Monomer ||Abbe value |
|1.499 ||CR39 ||57 |
|Specific Gravity ||Transmission ||Coat |
|1.34 ||97% ||HC |
|Diameter ||Spheical ||Cylinder |
|65mm ||0.00~+-20.00 ||0.00~-6.00 |
The advantages of the 1.499 CR39
1) It’s inexpensive, since it’s been around for over 70 years. Optically speaking, it has a good, reasonably smooth refractive surface, and very little distortion at the edges of the lens
2) The big advantages of CR39 lenses over previous glass lenses were light weight, and better shatter resistance. The lower weight allowed eyeglass makers to experiment with larger size lenses, since CR39 is much lighter in weight.
3) Although CR39 has better shatter resistance than glass lenses, it still can shatter under a strong impact. For this reason, more and more optical professionals are moving to newer lens materials (polycarbonate and others, to be discussed in future posts) that are almost impossible to shatter.
4) Far lighter than a glass lens
5) A proven high quality in a wide range
6) Exists in all design and value-added treatment
7) For all wearers looking for a simple, exonomical lens