Because they share similar properties – such as high impact resistance, light weight, 100% ultraviolet light blockage, and excellent strength – Trivex lenses and polycarbonate lenses are often confused or considered interchangeable.
Polycarbonate vs. Trivex Lenses
The two lens materials are indeed relatively close in several categories, but do have distinctive properties than set them apart. Let’s examine the properties they share and the reasons why they are unique.
Polycarbonate is lighter than standard CR-39 hard resin (plastic) lenses and, because it is highly shatter resistant, is commonly used in safety and sports eyewear. It boasts the highest impact resistance of any lens material. Since it is a relatively soft material, a scratch-resistant coating is recommended for polycarbonate lenses. The light weight and resistance to cracking make it a common material choice for rimless or semi-rimless frame styles.
The main drawback to polycarbonate is its low Abbe value. Abbe value is the measure of chromatic aberration (or lens distortion); the lower the Abbe value, the more aberration is present in the lens. Polycarbonate has an Abbe value rating of 30, which makes it second only to 1.8 high index glass in terms of optical quality. Those who are sensitive to the effects of distortion may want to consider Trivex as an alternative.
Trivex is made of a urethane-based pre-polymer. It is the lightest of all modern lens materials but is strong enough to endure a high level of impact, making it an ideal choice for sports glasses and safety goggles/glasses. Better yet, with an Abbe value of about 44, Trivex shows a significant improvement over polycarbonate in optical clarity. Price can be a determining factor here, as Trivex generally costs about double the amount of polycarbonate.
Here are the pertinent statistics for both materials:
TRIVEX
Refractive Index is 1.532
Abbe Value of between 43-45
Density of 1.1 g/cm³ makes it the lightest corrective lens material in common use
Ultraviolet Light Cutoff of 380nm
Blocks 100% of the sun’s harmful ultraviolet rays
Compatible with most applied external coatings, such as an anti-reflective or scratch-resistant coating
Compatible with digitally-surfaced progressive and single vision lens designs
Compatible with polarized or photochromic (transition) lenses
POLYCARBONATE
Refractive Index is 1.586
Abbe value of 30
Density of 1.2 g/cm³
Ultraviolet Light Cutoff of 385nm
Blocks 100% of the sun’s harmful ultraviolet rays
Compatible with most applied external coatings, such as an anti-reflective or scratch-resistant coating
Compatible with digitally-surfaced progressive and single vision lens designs
Compatible with polarized or photochromic (transition) lenses