 Welcome to our Special
Edition of EYEZONE magazine:
a review of photochromic lenses
provided by Transitions Optical.
Photochromic technology has come a
long way since its invention in 1966.
Today’s products are light years ahead
of their ancestors, and photochromic
sales reflect the growing number of
people who choose to wear them.
Photochromic technologies now exist
for mineral, organic, and corrective clear
lens designs, as well as motorcycle helmets
and sunwear. This guide has been
written to provide you with an easy-toread
summary of the various technologies
and choices you can offer your customers.
If you are not already aware, you
will soon become convinced that there
is a photochromic lens for every one of
them. This guide aims to give you greater
confidence when recommending
photochromic lenses to your customers.
Should you have any questions not covered
in this special edition, please let us
know: Transitions Optical
Mobile: +971 50 659 4664
Fax: +971 8 448 1337
E-mail: welali@transitions.fr.
Transitions Optical would like to thank
EYEZONE magazine for their support in
making this special edition possible.
Contents
1. Photochromism and
Photochromic Technology
1.1. Photochromism Definition
1.2. Applications in the
Optics Industry
1.3. Lens Material
1.3.1. The optical market: A steady shift to
organic lenses
1.4. Photochromic Dyes
1.4.1. For mineral lenses
1.4.2. For organic lenses
1.5. Manufacturing Process
1.5.1. In-Mass process
1.5.2. Surface technologies
1.6. Photochromism:
A Growing Movement |
1. Photochromism and Photochromic Technology
1.1/ Photochromism Definition
Photochromism is a reversible colour change
caused by the exposure of a material to visible
or invisible light. It is derived from the Greek
words phôtos (light) and khrôma (colour).
1.2/ Applications in the Optics Industry
Photochromic lenses change colour in response
to a chemical reaction triggered by UV rays.
When UV exposure ceases this chemical reaction
moves in the reverse direction, causing the
lenses to fade back to their initial colour.
Photochromic technology depends on three
key elements:
Lens material matrix
Photochromic dyes
Manufacturing process
1.3/ Lens Material Matrix
The lens matrix is the foundation of photochromic
lenses, and may be composed of either organic
or mineral materials:
| Mineral
(Glass) Lenses |
Organic (Plastic)
Lenses |
Scatch resistant
Heavier
Breakable |
Less scratch
resistant
Light-weight
Impact resistant
Better at filtering UV |
1.3.1. The optical market: A steady shift to organic
lenses
Mineral lens sales have been dropping steadily
for several years, and photochromic mineral
lenses have therefore steadily given way to
photochromic organic lenses in many markets
around the world. This transition is driven both
by the basic advantages of organic lenses —
lighter, sturdier, easier to make, etc — as well as
the inherent limitations of the in-mass process
used to make all mineral photochromic lenses.
In in-mass process of production is discussed
further later in this edition.
1.4. Photochromic Dyes
1.4.1. Mineral lenses
Mineral lenses were the first photochromic
lenses on the market. The technology used to
make these lenses consists of incorporating
silver halide crystals into the mineral material.
When exposed to UV rays, these silver halide
crystals react and darken in a chemical reaction
called oxidoreduction. The UV rays induce the
oxidation of the chloride ions to chlorine and
the reduction of silver ions to silver atoms. The
silver atoms then cluster together, blocking the
transmission of light, thus causing the lenses to
darken. The level of darkening is temperature
dependant.
1.4.2. Organic lenses
Silver halide crystals are not compatible with
organic materials, therefore lens manufacturers
use organic photochromic dyes instead. When
exposed to UV rays, these dyes undergo structural
changes that modify the light transmission
properties of the organic lenses. This structural
change is driven toward the coloured state by
UV light and toward the colourless state by ambient
heat. Thus, when UV exposure ends, the
molecules naturally return to their initial structure.
Transitions lenses, for example, are organic photochromic
lenses that were first marketed in the
early 1990s. Transitions Optical uses a family of
special molecules incorporated into their lenses,
called diaryl naphthopyran (DANP). This family
of photosensitive molecules includes many
dyes, each of which produce a specific colour
when activated. The particular type and proportion
of the different dyes are responsible for the
specific properties of a photochromic lens, including:
* Colour
* Activation speed
* Uniformity of colour
* Durability
Transitions Optical has developed and evaluated
several dyes. They are currently selling the sixth generation of their lens product.
1.5. Manufacturing Processes
There are two main types of lens fabrication
techniques: The first is internally cast or “inmass”.
The second uses surface technologies.
1.5.1. The “in-mass” process
In-mass or internally cast lenses have photochromic
molecules embedded throughout the
lens substrate. All mineral lenses are produced
in-mass by incorporating silver halide crystals
into the casting phase. Some mid-index organic
lenses also use the in-mass process by incorporating
photochromic dyes into the liquid monomer before polymerization.
“We believe that Vision-X Dubai is the only major
show that covers the whole region. Looking into the
optical industry, there is no other exhibition around
us that could provide much coverage and exposure
for us and any other company that is participating,”
Eghterafi explains his opinion on taking the main
sponsorship at the exhibition.
|
In-Mass Process: Advantages &
Disadvantages
The in-mass process is relatively easy to deploy on an
industrial scale and has therefore some economic advantages. However, it
also has some disadvantages:
*
The
non-uniformity of the lens in its activated state: Because
photochromic molecules are
distributed throughout the material, rather than only on the surface
where they are needed, the lens may be darker where it is thicker,
i.e. in the centre for convex lenses and around the edges for concave
lenses. These effects have been termed “bull’s eye” and “raccoon”
effects.
In addition to being unattractive, this non-uniformity is
uncomfortable for the myopic wearer. Indeed, the lens is less tinted in
the centre, the very part where the focus of the wearer is concentrated.
*
A residual tint indoors (in a
deactivated state) because of the excessive photochromic
molecules throughout the lens.
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1.5.2. Surface technologies
Surface technologies involve incorporating
the photochromic dyes on the front surface of
the lens. Manufacturers use one of two types
of processes: imbibition (or deep coating), and
surface coating. Transitions Optical uses its
own variation of surface coating called “Transbonding”
TM. Transitions Optical, as a “Lens-Converter”,
has pioneered the surface technologies
area and can process lenses supplied by most
lens casters — including over 70 progressive
lens designs.
“Imbibition”
Transitions Optical is the only company to use the imbibition process. Most other lens manufacturers use in-mass casting or other surface coating technologies.
The imbibition process in 3 key steps:
1. Application of the photochromic product to semi-finished or finished lenses
A coating containing photochromic dye is deposited onto the centre of the lens surface. The lens is secured on a rotating arm, which ensures that the photochromic resin is uniformly distributed on the surface of the lens through centrifugation.
2. The thermal process
The lens is then placed in a high-temperature oven. When exposed to heat, the lens matrix opens and photochromic dyes penetrate into the lens material. Once the lens matrix closes, the dyes are “trapped” and are an integral part of the lens matrix. The photochromic dyes are said to have “migrated”, “diffused”, or “imbibed” into the substrate. The coating, now depleted of photochromic dye, is rinsed from the surface of the lens.
With this exclusive, Transitions®-patented process, the photochromic dyes penetrate deep into the substrate and become an integral part of the lens.
Because photochromic dyes are placed only where needed – onto the front surface of the lens – the imbibition process results in photochromic lenses with
indoor clarity and a consistent coloration in the activated state.
Furthermore, because photochromic dyes have “migrated” into the substrate, they cannot be scratched.
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3. The application of a protective layer
A protective hard coat is then applied by spin- or dip-coating to protect the surface of the lens. Transitions® lenses are then shipped to lens manufacturers or labs, who:
• Add anti-reflection, water-repellent, anti-smudge and other coatings to the front and back surface of the lens, based on demand
• Market the lenses as part of their product lines
Surface Coating and Trans-bondingTM
Surface coating consists of “attaching” the photochromic dyes to the surface of the lens in a separate polymer based coating matrix. This photochromic coating must provide good adhesion to the substrate lens. It must also be soft enough to provide for fast photochromic darkening and clearing, yet hard enough to provide a good base when applying a brittle hard coat or anti-reflective coating over the top.
Trans-bondingTM
Not all lens materials are suited to the imbibition process and, as a result, Transitions Optical developed the Trans-bonding™ process
for high index and polycarbonate lenses. Other lens manufacturers have used surface coating for high index and polycarbonate lenses. But Trans-bondingTM differs from other surface coating in that it involves surface preparation stages and multi-layer coating application to produce the final photochromic lens product. Transitions Optical has continued to optimize the TransbondingTM process to ensure robustness and compatibility with subsequent coating layers, such as anti-reflection coatings.
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1.6. Photochromism: A Growing Movement
Photochromics are a growing share of the total lens market, partly due to consistent technological improvements in the manufacturing process. It now accounts for a significant share of the optical market all over the world. In Europe, for example:
More than 1 out of every 10 prescriptive lens customers choose photochromic lenses
More than 1 out of every 7 progressive lens customers opt for photochromic lenses
For eyecare professionals, photochromic lenses represent an opportunity to increase added value in a crowded market place — where the battle for margins is raging and constantly fuelled by aggressive promotional offer.
Question and Answer with Alexis Cardona
 We have asked Alexis Cardona, the Chief Marketing Officer at Transitions Optical, to help explain how being adaptive helps to stay ahead of current trends in the optics market.
Q: You’ve recently joined Transitions Optical, what is your background?
A: I have 17 years of marketing, brand-building and business management, 15 of which were with Procter & Gamble leading various regional and global businesses in categories such as Cosmetics, Food & Beverage, Oral Care, Baby Care and Fabric Care amongst others; with brands such as Cover Girl, Oral-B, and Pampers. In addition to brand management, I have also gained quite a bit of experience in developing shopper marketing, multicultural marketing, new product design and innovation, and global brand franchise leadership in both start-ups as well as more established organizations.
Q: What is your vision for Transitions Optical?
A: Well, it’s still very early in that I only very recently joined Transitions Optical. However, I can say that I am extremely excited by the fantastic business Transitions has developed – and even more excited by the potential to drive the business and brand even further. I think the vision that we all share at Transitions Optical is that we continue our journey to becoming a world-class, brand-driven company that leads the optical industry – and the consumer and professional marketing fields – in both product and brand marketing innovation. I think there is also potential for Transitions Optical to further redefine the business from photochromics to adaptive eyewear and eyecare that is relevant to your every need and lifestyle. I believe Transitions lenses can become the indispensable everyday lens of choice for any consumer that uses eyewear.
Q: What are the main challenges for the business in the coming years?
A: I think an ongoing challenge will be to keep up with the pace of change in technology and industry consolidation. Technological change is accelerating and it will be necessary for Transitions Optical to remain nimble and react quickly to opportunities – evaluating the impact to the business model and how we can adapt to better meet the needs of our lens caster partners, eyecare professionals and consumers while maximizing the potential for us. Also, industry consolidation and new emerging channels (such as e-commerce and mega-labs) are also a challenge as the lines between channels and our retail and lab partners are blurring and being redefined, so our go-to-market approaches to reach the consumer have to anticipate these changing conditions. However, this creates an opportunity to be first and be better at meeting new channel needs and get to the consumer and eyecare professionals better, faster, and more accurately. Another significant challenge is the increasing globalization of the consumer and eyecare professional and increased discrimination in their wants and needs; while the ways to reach them (marketing mediums and media vehicles) grow increasingly fragmented. It will be more challenging to effectively build the equity and relevance of our brand with consistency and efficiency; but again, it is an opportunity to have a more direct two-way conversation with consumers and eyecare professionals in ways that truly build a relationship. This results in more advocacy and loyalty – and allows us to consistently capture input from our consumers so we create more relevant, meaningful product offerings.
Q: We see more and more on line/ direct to consumer offer to buy prescription lenses in a lot of countries. Where do you see the professionals in this new business model? How do you think the role of the professionals will evolve in the coming year?
A: We know for sure that one of the single most important factors that drives purchase by the consumer is an eyecare professional recommendation. Not only does the recommendation of an eyecare professional dramatically increase purchase intent and credibility, it often results in a higher investment amount and in increased consumer category involvement. This is because he/she trusts the eyecare professional implicitly and the professional, given their knowledge and expertise, can guide the consumer to understand that a purchase is an investment in better eye health in the short- and long-term, not just an accessory purchase. So investing in the right eyecare solutions becomes of much higher value. I don’t think this will change – consumers will always look for the expertise, education and knowledge of an eyecare professional; and with increasing education consumers know that a prescription is critical to choosing the right eyewear. What will evolve is how and where eyecare professionals interact with consumers – they will have to ensure they are present and having active dialogue and conversation wherever consumers go to fill a prescription, which may increasingly be online. Further, as digitalization becomes increasingly sophisticated it may open doors for eye examinations and prescriptions to happen remotely via digital channels. I think it is critical for eyecare professionals to lead in this arena. |
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