On a quest to find the perfect lenses for your prescription? You’ll want to make sure you’re selecting the lens material that works best for your frames, your prescription, and you! Having a lot of options is great, but can easily become quite an ordeal if you don’t understand the differences between them!
This is our most basic offering for prescription and non-prescription lenses. CR-39 is a plastic polymer with excellent clarity, but is also our thickest lens material. We would recommend this material for non prescription lenses, as well as those with a sphere between -2.75 to +2.00.
Refractive Index: 1.498
Abbe Value: 58
Compared to CR-39, polycarbonate is a lighter and significantly more impact-resistant lens — making it a preferred material for children’s eyewear, safety glasses and sports eyewear. We would recommend this material for those with a sphere above +2.00, or below -2.75. If you have a rimless frame which would require any drilling to mount, polycarbonate would also be the way to go!
Refractive Index: 1.586
Abbe Value: 30
Thin, Ultra: High-Index Lenses
These lenses are thinner and lighter than CR-39 and polycarbonate plastic lenses because they have a higher index of refraction, and may also have a lower specific gravity. 1.74 lenses are the thinnest lenses on the market currently. If you have a strong prescription, we would recommend a high index lens, as they provide the most comfort.
Refractive Index 1.67, Abbe Value: 32
Refractive Index 1.74, Abbe Value: 33
What is Abbe Value?
The Abbe Value is a number given to describe the amount of chromatic aberration of a lens material. The higher the number, the less amount of aberration — which means more clarity. Standard CR39 lenses have the most clarity, with high index leading after that, and then polycarbonate with the lowest abbe value.
Check out this lens chart to see how different lens materials are cut at different powers!