'Life-proof' lens coating technology

First developed 30 years ago, Crizal lenses have set the standard of anti-reflection coatings. Essilor has now improved the portfolio with new lens coating technology that, among other features, have improved the resistance of its lenses.

Essilor Group’s origins are bedded in a unique human, industrial and business venture, starting in 1849 as a Parisian artisanal spectacle maker before evolving into an optical industry powerhouse.

With a 173-year history, the global ophthalmic lens manufacturer considers itself at the core of technological advances propelling the industry forward, notwithstanding innovations like the world’s first progressive lens (Varilux) in 1959 and other breakthroughs like the 1.5 index plastic spectacle lenses and an automatic edging machine.

The fact half of the group’s revenue today comes from products designed less than five years ago perhaps speaks volumes of its emphasis on R&D, which now amounts to more than €350 million (AU$550 m) annually.

During the past four years, the company’s Crizal lens coatings – first launched in 1992 – have been a major priority of its R&D program.

Specifically, Essilor has aimed to develop new technologies that continue to deliver anti-reflection properties, in addition to improved scratch and thermal resistance, and anti-smudge and UV protection benefits. The focus has been on producing “life-proof” lenses. As a result, the new Crizal portfolio is now protected by up to 10 patents.

While already available in some markets, Australian eyecare professionals and their patients will have access to the updated Crizal coatings from this month.

In short, the new Crizal Sapphire HR will replace Essilor’s flagship coating Crizal Sapphire UV. Crizal Rock will replace Crizal UV. Crizal Easy Pro will replace Crizal Easy, while Crizal Sun XProtect will replace Crizal Sun UV.

Ms Tara McCabe, Essilor’s Sydney-based director of marketing and business partnership, says since Crizal coatings were first developed the company has been working to “redefine the standard of anti-reflection coatings for all wearers”.

More than 825 million Crizal lenses have been sold – equating to a pair sold every second worldwide – and Essilor is now seeking to build on this with its upgraded portfolio.

“Our flagship product, Crizal Sapphire UV, has been the most popular and fastest growing coating in the Crizal range,” McCabe explains.

“With its unique anti-reflection benefits from not just the front but also the back and sides – the lens is almost invisible. Vision is virtually free from disturbing reflections, light sheen, ghost images and back and side reflections. This feature is in addition to the outstanding anti-scratch, anti-smudge, ease of cleaning and UV protection benefits that Crizal Sapphire HR now provides.”

Explaining the technology further, McCabe says Crizal Sapphire HR is the portfolio’s best anti-reflection coating overall.²Compared to previous generations, it has a 70% improvement in scratch resistance and 20% increase in thermal resistance. It’s also easy to clean with superior smudge and water resistance. Additionally, Crizal Sapphire HR is said to offer “best in class transparency”, matching the anti-reflection efficiency of Crizal Sapphire UV.

Crizal lenses have been a leader in anti-reflection coating technology.

According to Essilor, there are three innovations underpinning the coating. The first is Multi-angular Technology that reduces front, lateral and back reflections. The second element is High Resistance Technology, a combination of four specific oxides known for their resistance against scratches and temperature (one oxide is used in the aerospace industry). The third feature is High Surface Density Process; this produces a super hydrophobic and ultra-smooth topcoat for smudge resistance and a superior ability to repel dirt and water, Essilor states.

McCabe says the second lens coating in the portfolio, Crizal Rock, offers Essilor’s best combination of scratch and smudge resistance², whilst maintaining reduced reflections, UV protection, plus water and dust repellence.

Like Crizal Sapphire HR, it also features High-Resistance Technology. Crizal Rock is also bolstered by High Surface Density Process technology in the topcoat for ease of cleaning.

Next up, Crizal Easy Pro, is described as an easy to clean and maintain anti-reflection coating featuring High Surface Density Process in the topcoat to resist smudges and repel water.

Additionally, all three – Crizal Sapphire HR, Crizal Rock and Crizal Easy Pro – offer UV protection of E-SPF 35.5 High level UV protection is offered with all lens materials (clear CR39 is slightly lower giving ESPF 10), blocking 100% of transmitted UV, while the coating’s special UV layer cuts rays reflected from the back lens surface.

Finally, Essilor has developed Crizal Sun XProtect exclusively for its Xperio tinted and polarised sun lenses. Its Ionic Shield Technology is applied by vacuum deposition, a patent pending formulation reinforcing the front surface of the sun lens for best-in-class scratch resistance, while fluorinated molecules add superior smudge protection, keeping Xperio sun lenses looking newer for longer.⁹ Crizal Sun XProtect offers UV protection of E-SPF 50¹² and has a subtle gold lustre on the front surface for a fashionable, premium finish.

A chance to add value

While Crizal coatings add features that enhance the performance of Essilor lenses, McCabe says it also offers a unique opportunity for Australian practitioners to increase customer satisfaction.

“It allows the practice to offer higher value vision solutions and differentiate themselves from practices offering lower value and lower performing coatings. This contributes to added value and profitability to the optical business,” she explains.

“We’ve seen the pandemic further reinforce the importance of good vision and eye health. With the increased use of screens, it’s even more important to reduce reflections, increase light transmission and improve contrast. With the frequent use of video calls, reflections from a wearer’s glasses can be distracting and unappealing for viewers. Providing optical lenses protected by an anti-reflection coating are key.”

Additionally, McCabe says UV protection remains critical for eyes and surrounding skin. While patients are aware of the harmful effects of UV head-on, many are less aware of the potential impact when sunlight is reflected off the back lens surface from behind.

“Lenses with Crizal coatings combined with hi-index plastic lens materials*, reduce UV impacting the eye from both the front surface transmission but also from back surface reflection,” she says.

“We are also the only manufacturer that uses the E-SPF rating system giving patients a simple way to understand the UV protection level of their lens coating.”

Tried and tested

To put its new Crizal technology to the test, Essilor has developed a protocol of technical and consumer trials to verify in-life performance and assess a lens’ resistance to scratches, smudges, and daily wear and tear.

The most notable of these is a new Sand Resistance Test, providing a more controlled and repeatable test with greater capacity to discriminate between high-scratch resistant coatings than the historical Bayer test. In this test, lenses were subjected to 300 shake-cycles in a sand filled tray; Crizal Rock and Crizal Sapphire HR showed a 70% increase in scratch resistance versus Crizal UV.

A separate extensive Cleaning Test – conducted by an external lab – replicated daily cleaning over the lens’ life. It involved 20,000 wipes with ink splattered on the lens every 5,000 wipes. Crizal was shown to be the easiest to clean lens.⁶

Essilor has also conducted consumer tests, including an 18-month trial in which its R&D experts evaluated the difference in abrasion level between Crizal Rock vs Crizal UV, worn in parallel. In this, Crizal Rock had superior scratch resistance over the previous generation of Crizal.⁸

And to push Crizal lenses to their limit – a Unique Torture Test was conducted on Crizal Rock. After a battery of wipes, rubs, shakes, drops and hits before a panel of observers, an independent third party certified the “lenses are in new condition, without any scratches or dents”.

Finally, third party testing, simulating up to two years’ real-life usage, validated Xperio sun lenses with Crizal Sun XProtect can withstand everyday wear and tear and last longer than Crizal Sun UV. Performance was more than two times better against scratches¹⁰ and the same for smudge resistance.¹¹

Innovation in the blood

With this in mind, Essilor ANZ CEO Mr Pierre Longerna says it’s clear R&D sits at the core of the group. While many innovations propelled the company in the second half of the 20th century, it’s from the 1990s that the biggest changes have occurred, including the Crizal coatings portfolio.

“As computing power grew so did Essilor’s R&D capabilities. Lens designs, coatings and even materials are all dependent on data and calculations and with more computer power the bigger the calculations that can be performed,” he explains.

“There are a number of Essilor R&D facilities scattered around the world dealing with everything from lens design to materials and processes; fundamental optical science to myopia and wearer perception. I think there is some sort of Essilor R&D conducted on just about every continent on the globe – we’ve even done a wearer test in Antarctica.”

While most will recall the first progressive invented by the late Dr Bernard Martinez in 1959, he says fewer people recognise Essilor was also the first to bring other important innovations to market.

“These include the 1.5 index plastic spectacle lenses in 1963; the first automatic edging machine; the first extended focus lens in 1988; the first low power full-field aspheric single vision lenses in 1989; the first anti-fatigue lens in 2004 and even the first hard multi-coat on plastic lenses,” he says.

“Most of these products have been the mainstays of the development of the industry in the last 35 years or more.”

*Used with all materials except clear 1.5 index Crizal coatings offer ESPF 35.

References

Based on Brand tracking 2017 – MSW – 19 countries – 16.746 eyeglass wearers, 668 Crizal® wearers. Countries: Australia, Brazil, Canada, China, Colombia, France, Germany, India, Italy, Malaysia, Mexico, Philippines, Russia, Singapore, Spain, Taiwan, Thailand, United Kingdom, United States of America.
External laboratory tests and internal technical tests in 2020. Compared to the most known lens-brands by consumers (2019 external brand tracking in 11 countries). The word ‘overall’ refers to consumer expectations about anti-reflective coatings, ranked through a quantitative consumer study run by an external institute in 3 countries.
Within Crizal® Range – External laboratories tests and internal technical tests in 2019 – compared to all previous generations of Crizal® coatings.
External laboratories tests and internal technical tests in 2019. Combination here defined as the merger of 2 distinct criteria which are scratch resistance and smudge resistance – Crizal® Rock™ rated best on smudge resistance and equal on scratch resistance, compared to the most known lenses brands by consumers (MSW brand tracking 2018 in 17 countries). Scratch resistance may vary depending on lens configuration.
Except clear 1.5 index: E-SPF 10. E-SPF35™ can be attained when combined with Blue UV Capture™ on a 1.5 Index lens.
Based on the stain release test, amongst globally known lenses brands by consumers (MSW brand tracking 2018 in 17 countries).
Communicated by a lens manufacturer.
External laboratories test and internal technical tests in 2019, among the most known lenses brands by consumers (MSW brand tracking 2018 in 17 countries. Essilor® R&D Wear test 2019 – n=48 eyeglass wearers – abrasion level on a 7 points scale, significant difference between Crizal® Rock™ and previous generation of Crizal® with statistical student test.
Compared against coatings from main players in the prescription sun lens market. Based on data from ISTM Bayer test and Stain Release test conducted by independent third-party laboratory, 2020.
Based on data from ISTM Bayer test conducted by independent third-party laboratory, 2020.
Based on data from Stain Release test conducted by independent third-party laboratory,2020.
UV Protection indicates E-SPF® 50, does not apply for Orma (1.5 index) without UVX.