NXT/Trivex® Core

NXT/Trivex® lenses changed everything!

In the past there were fragile sunglass lenses with excellent optical properties or tough lenses with poor optical properties.

NXT® was formulated in the early 1990’s for the wind-shields of a new generation attack helicopters. The new material needed to be bulletproof, lightweight and optically superior.

After years of intensive research to optimise the technology, Bigatmo’s NXT/Trivex® lenses are the next step in its evolution.

Next Generation optical properties

All Bigatmo lenses are made from NXT/Trivex® material. They are formed in glass moulds with long, carefully controlled curing times, producing lenses with very low internal stresses. The result is a clear lens with advanced optical properties and virtually no chromatic aberration. It’s easy to see the difference with NXT/Trivex®:

Polariscope images show internal stresses in lenses. Bigatmo NXT/Trivex® lens on the left, regular polycarbonate lens on the right.

Polariscope images show internal stresses in lenses. An NXT/Trivex® lens is on the left, and a polycarbonate lens is on the right.

Low internal stresses are just one of the measures used to evaluate the optical quality of a lens: Bigatmo NXT/Trivex® lenses also have a much higher abbe number than polycarbonate (improving the clarity of the lens) a refractive index that makes them ideal for both plano and RX applications, and a low surface reflection (reducing glare). Combined with the strength and toughness of NXT®, these elements result in a truly unbeatable lens.

Bigatmo Chromatic Aberration - NXT left, polycarbonate right

Images comparing chromatic aberration between a Bigatmo NXT/Trivex® lens on the left, and a polycarbonate lens on the right.

Strength and Protection

Let’s have a look at how NXT/Trivex® performs in the areas of impact resistance and also UV radiation protection. Additionally, there’s a paragraph on chemical resistance.

NXT® has been described as clear armour. A sheet just 6mm thick will stop a .22 bullet. The video shows an NXT® block stopping a 9mm round dead in its tracks:

Our lenses are less than 2mm thick and certainly aren’t bullet proof. However, NXT/Trivex® is by far the strongest lens material on the market *. It passes ANSI’s High-Velocity Impact Test; a stringent test where 1/4-inch steel spheres are fired at the lens at a velocity of 150 feet-per-second. If an NXT® lens is hit, the material returns to its original shape with virtually no residual distortion.   In fact, it’s hard to see the impact point on NXT®:

Effect of impact on Bigatmo NXT® lens (left) vs. regular polycarbonate lens (right)

Effect of impact on a Bigatmo NXT® lens (left) vs. regular polycarbonate lens (right)

* It’s worth noting that impact resistant lenses cannot be classed as either shatterproof or unbreakable and that coatings may alter the impact resistance of any lens material.

NXT/Trivex® also doesn’t suffer from stress cracking or hairline cracks – making lenses extremely durable and long lasting.

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). NXT/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 the lenses inherently absorb harmful UV wavelengths.

Chemical Resistance – NXT/Trivex® features extreme resistance to common home and office solvents, such as ammonia or acetone (nail varnish remover) or even gasoline. There is far less likelihood that innocent exposure to these chemicals will accidentally damage or destroy an otherwise perfectly good lens. All Bigatmo lenses feature multi-coatings which might be less durable.


With a specific gravity of 1.11 (g/cm³) NXT/Trivex® is just about the lightest lens material available. This helps make our sunglasses really comfortable to wear for long periods of time. It’s easy to forget you’re wearing them. For comparison, the most common materials used for sun lenses are Polycarbonate (sg 1.22), CR39 (sg 1.32) and crown glass (sg 2.53).

Lightweight Alutra lens

Lightweight Alutra lens

Available in three different lens options

Whilst NXT/Trivex® is the core material of all Bigatmo lenses, there are three different lens options to suit your lifestyle.

Bigatmo Alutra lenses deliver a punchy view of the world with excellent vibrant colour acuity and high definition optics. The photochromic core is perfect for when you’re out and about moving between sun and shade, and also allows you to comfortably read instrument panels in high contrast environments like the flight deck or when driving.

Bigatmo Zeolite lenses use advanced Light Management Technology to enhance colours by filtering out the wavelengths that fall between red, blue and green – the primary colours in which we see. Your eyes receive more specific colour information improving overall image sharpness and clarity.

Bigatmo Polarized lenses have the same colour enhancing technology as our Zeolite lenses, together with a polarizing filter which dramatically reduces glare from roads, snow, sea and sand, revealing all kinds of hidden details and textures in High Definition.