Optical quality of the lens

interesting to know that the optical quality of the lens affects how good the light is moving through the lens into our brain. it is measured by Abbe unit from 1 to 100 which the latter is the perfect one.
here is the Abbe of these 3 options:

  1. CR-39 - 58
  2. trivex - 43
  3. poly with index 1.61 - 41
  4. poly with higher index- the thinner the poly lens (the higher the index) the lower the vision quality you get, because if the lens is needed to be thinner then the material of the lens will need to be more compressed in order to maintain good impact resistence, which will affect negatively on the abbility of the light to move inside it into the eyes and brain (more shatter resistent less Abbe).

because I favor the rimless, I can’t use the CR-39 although if I am thinking about it now I do can ask for a rimless one with the cr-39 though most I will end up with the poly because the CR-39 is not good material for the rimless.

I wonder if any one have seen a significant difference with the cr-39 and a rimless eyeglasses with this one?

1 Like

[Sorry for the necro-posting, but these keep coming up as unread in my feed…]

From an optical quality perspective, it is my opinion that you almost always want the thinnest lenses to minimize the amount of optical distortion. Distortion compounds the further you get from the optical center of the lens and compounds more quickly with higher power lenses. So the higher the correction, the higher the index of the lens you want to have.

Abbe value is the relationship of the lens material index to color dispersion in the visual light spectrum. Higher Abbe values mean less introduced lateral chromatic aberration (color fringing), particularly when looking through the sides of a lens. However, Abbe values tend to follow an inverse relationship to material index. Therefore, higher index lenses have higher optical quality but also introduce more color fringing.

The ideal lens is the one that gives you the best balance between optical quality (index vs power) and the least chromatic aberration (higher Abbe rating).

From my own research, these are the best quality lenses available right now:

For low myopes, CR-39 Resin (1.498 index, 59 Abbe) or 1.5 Glass (1.523 index, 58 Abbe) are the best options. Glass will be pretty heavy though.

For mid power myopes, Trivex (1.53 index, 45 Abbe), Hi-Vex 1.56 (Abbe 46), and Xirm lenses (1.58, Abbe 43) are the best options. All are on the pricey side and Hi-Vex and Xirm can be harder to find outside of optical shops.

For people in the higher correction, HiVex MR-8 lenses (1.61, Abbe 41) are a great option. The MR-10 1.67 lenses offer good lens quality but Abbe value falls off quickly (Abbe 32).

For very high power myopes, your choices narrow to lower Abbe options that are quite expensive. The high-index 1.71 lenses (Abbe 36) are the best I’ve seen, but also harder to find. You can find 1.701 glass lenses (Abbe 40) and 1.80 glass lenses (Abbe 35) but they can get quite heavy.

I also prefer rimless and semi-rimless lenses. If it were me, I might consider Trivex instead of CR-39. From what I’ve heard, that handles drilling better and hold up well over time. Alternatively, there is a hybrid product called “High Index 55” (1.537 index, 47 Abbe) which is even better, but you will probably need to find an optical shop to get it.

Then again, neither option is probably ideal if you’re looking for glasses that will only last you a few months. Of course, when you’re in low diopters, those take a lot longer to get through so maybe it may still be useful. :slight_smile: