Material Properties

The unique composition of Trivex delivers material properties that combine to deliver crisp, clear vision and unsurpassed strength and protection in an ultra-lightweight lens.

Crisp, Clear Vision

Trivex material’s unique composition provides greater optical quality, optimizing eyewear and reducing eyestrain.

Abbe Value: Abbe value is a measure of the dispersion of light through a lens into its color elements. This dispersion is known as the chromatic aberration. The higher the Abbe Value, the more accurately a lens aligns the spectrum of light waves that pass through it. Lens materials with lower Abbe Values are unable to focus these light waves accurately, resulting in vision defects that appear as distracting fringes of color around dark type and objects—what is known as “chromatic aberration.”

Lenses made from Trivex material have an Abbe value ranging from 43 to 45. Compared to polycarbonate with an Abbe value of 30 and high index materials with Abbe values of 32 to 34, the high Abbe values of Trivex material mean that color aberration is virtually undetectable by patients who wear lenses made from Trivex material, even with higher powered lens prescriptions.

Percent Transmittance: As light travels through a lens, a certain percentage of that light is lost through absorption and reflection at each air-to surface interface. The amount of original light available to the eyeglass wearer by the time it exits the lens will vary depending on the quality of the lens material and type and amount of anti-reflection coatings applied to the lens surface. This is an important factor that directly affects the actual brightness of an observed image.

The term used to describe this percentage of light that is not lost is transmittance, and for most quality optical lenses this figure will usually be above 90 percent. When treated with A/R coating, lenses made with Trivex have one of the highest transmission levels of all commonly utilized lens materials at 91.4%. This means that patients will enjoy sharp, clear and crisp vision through lenses made from Trivex material.

Lightweight Comfort

Specific Gravity: Specific Gravity is a way in which weight of a lens material is specified. The lower the number, the lighter and more comfortable the lens will be. Anything with a specific gravity less than 1.0 will float on water.

The specific gravity of Trivex material is 1.11. This value makes it the lightest of all commonly utilized ophthalmic lens materials currently available. Compared to the density of CR-39 monomer (1.32), Trivex material is 16% lighter; compared to polycarbonate, it is 8% lighter, and nearly 25% lighter than high index (1.67 and 1.74) materials. So while high index lenses appear to be thin and light, they actually have a higher specific gravity because it is made from a more dense material. On the other hand, a lens made from Trivex material is so light that it almost floats.

When aspheric curvatures are used on lenses made with Trivex, even more thickness and weight reduction can be achieved.

Refractive Index: Trivex lens material has a 1.53 index of refraction. This mid-index value enables lenses made from Trivex material to be thinner, lighter and more comfortable. For example, when compared to lenses made with CR-39 monomer (with an index of 1.50) of the same power and diameter, lenses made from Trivex material are up to 50% thinner and 50% lighter resulting in improved comfort for the wearer. Due to the strength of the Trivex material, it can also be surfaced to a 1.0mm thickness thereby reducing the weight and thinness of the lenses even further.

Strength and Protection

For the demands of everyday living, eyeglass lenses need to provide protection from unexpected impact and breakage. Trivex provides high-impact resistance when it is needed most—for example, during participation in sports or in an active work environment.

Impact Resistance
Lenses made from Trivex material pass the ANSI Z87.1 High-Velocity Impact Test and the U.S. Food and Drug Administration (FDA) Drop Ball Test.

ANSI Z87.1 High-Velocity Impact Test: The American National Standards Institute (ANSI) has established the most stringent impact and projectile penetration standards for optical lenses. The standard specifies that high-impact lenses must pass “high-velocity” testing where 1/4-inch steel pellets are “shot” at the lens at a velocity of 150 feet-per-second.

FDA Drop Ball Test: In 1972 when the majority of spectacle lenses were made from glass, the required that “all lenses must be impact resistant”. Their regulation requires that all lenses must be capable of withstanding the impact of a 5/8 inch steel ball dropped from the height of 50 inches onto the horizontal upper surface of the lens.

Note: Impact resistant lenses are neither shatterproof nor unbreakable.

UV Absorption
Ultra-violet (UV) radiation can have damaging short-term and long-term effects on essential parts of the eye. The wavelengths that pose these problems fall below the visible spectrum starting at 400 nanometers (nm). Trivex lens material filters out the harmful UV-A and UV-B wavelengths naturally thereby providing 100% UV blockage up to 394nm. This means that it is not necessary to dye lenses made from Trivex material to obtain this level of UV protection – the lenses inherently absorb harmful UV wavelengths.

Chemical Resistance
Lenses made from Trivex, polycarbonate and CR-39 materials were tested according the ISO 175* test method for chemical resistance. Each lens was immersed in separate containers of various chemicals commonly used in lens laboratories such as acetone (featured in this section) for 10 days. The test measures the changes in weight and diameter of the lenses after soaking as well as allows for a visual inspection for changes in clarity. The lenses made from Trivex and CR-39^TM materials did not register any change in weight, diameter or clarity. The polycarbonate lenses turned solid white after being soaked in acetone as shown in the photograph.

Results from tests performed at COLTS Laboratory in the U.S. (an independent laboratory) reveal that lenses made from Trivex material are also resistant to household chemicals such as bleach, salt water, WINDEX, sun tan lotion, and nail polish remover.

* International Standard BS EN ISO 175:2001 BS 2782-8:Method 830A: 1999, Plastics – Methods of test for the determination of the effects of immersion in liquids chemicals

The Trivex Material Advantage for Rimless Eyewear

Rimless eyewear has unique set of challenges; and many eyecare professionals have encountered disappointed patients who have had their lenses crack or fracture. Not only is this situation frustrating to the patient, it is also difficult and costly to the eyecare professional. As a person wears a rimless mounting, the lenses and mounting parts flex. This places stress on the lenses. Because of the flex and stress, the holes of some lens materials tend to stretch out of shape (known as hole elongation) making the lenses loose over time. Rimless lenses made from Trivex material are extremely durable and tough enough to withstand the stress associated with rimless eyewear.