Lens Materials

We at BLOK® sunglasses pride ourselves on offering the greatest optical quality for our customers. One of the lens materials we use is Columbia Resin 39 (CR-39).

CR-39 revolutionised the optical industry as the first plastic lens material to be invented. It is still the most widely used lens material throughout the world in the optical industry – for the following reasons:

  • It has the highest abrasion / scratch resistance of any uncoated optical plastic.
  • It is about half the weight of glass, but with similar optics and clarity.
  • It is resistant to most solvents and other chemicals, gamma radiation, aging, and to material fatigue.
  • It can be used continuously in temperatures up to 100 °C. It can even withstand small hot sparks from welding, something glass cannot do.
  • It has less Chromatic Aberration than all other plastic lenses.

All of these features have proven CR-39 to be the perfect material for eyeglasses and sunglasses.

 

The Australian CR-39 Story …

 You might be interested to know that the first experiments of casting CR-39 lenses evolved from humble beginnings in Adelaide, South Australia.

 In 1956, a group of men led by Noel Roscrow, who worked for prominent optometrists Laubman & Pank, used a gas ring and a saucepan in their garage to experiment with the production of plastic lenses. This small group of Australian entrepreneurs were determined to cast lenses in the early forms of the CR-39 material.

 In 1960, after modest success, Roscrow formed a new company called Scientific Optical Laboratories of Australia, now known as SOLA. Manufacturing lenses with this CR-39 resin was still a new and mysterious process – Roscrow and his team had no one to tell them how to do it. SOLA concentrated on Plano (non-prescription )lenses but they soon realised that, as big as Australia was, it was not big enough to support the kind of manufacturing plant they envisioned for themselves. So they expanded into UK, Japan, Italy and Brazil.

Years later, when the FDA in the US laid down heavy restrictions on the use of glass lenses, SOLA hit the jackpot with their much lighter CR-39 lenses and launched a major expansion into USA.

Today, SOLA operates 12 manufacturing sites on five continents with sales offices in 16 countries. Every week, SOLA customers worldwide, order more than one million lenses. The company estimates that more than one hundred million people around the world are wearing SOLA lenses today. A testament to the popularity and versatility of this high resolution optical lens material.

Even those optimistic young dreamers in Adelaide couldn’t have foreseen what would result from those primitive early attempts to make plastic lenses in a backyard garage.

 

Polycarbonate (PC) lenses

Polycarbonate is a very durable material. Although it has high impact-resistance, it has low scratch-resistance and so a hard coating is applied to polycarbonate eyewear lenses.

These lenses are virtually unbreakable and are much safer for sporting and hazardous activities. 

 

 

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