Quantum Mechanics...

[Pete Hanlin]

No, this isn't a question about physics- or maybe it is, I don't know. What I'd like to know is how the new Quantum technology is different than Transitions III.

I know that, in the Quantum lenses, the photochromic agent is found throughout the lens- not just in the surface, and that it can only be put into mid-index lenses.

What I'd like to know is why, how, and so on... I've always assumed the photochromic agent in plastic lenses (the name escapes me at the moment) isn't put into the whole lens because it is somehow incompatible with liquid resin.

I'm writing an article for our patient newsletter, and I'd like to have more knowledge on the lens (cause they always seem to come in with questions) than is provided at the booths you manufacturers have at the shows!

So, in general- how's it work???

Thanks,
Pete

[Jo]

Pete:

The "How Stuff Works" page is pretty simplistic but there are a couple of links at the bottom that may be helpful.
http://www.howstuffworks.com/question412.htm

[Darryl Meister]

Hi Pete,

Although there are photochromic plastics on the market that contain photochromic molecules throughout the lens blank (or "in mass"), the Quantum generation photochromics are imbibed into the front surface of the material -- as with conventional Transitions lenses. In the case of poly and 1.66 materials, it is imbibed in the front side coating (then there is a hard coating both below and above the photochromic layer).

The important thing is that simply putting the photochromic dyes in the mass of the material doesn't make them work faster, get darker, or last longer -- that is a result of the chemistry of the lens and dye working together. By the way, the chemical used in conventional Transitions lens materials was something called "indolino spironaphthoxazine." That's a mouthful, eh?

Bernadette Hiskey, our Director of Product Marketing, also explained that for Spectralite Velocity(tm) Transitions(r) we use the Quantum Transitions latest greatest dyes (fast reacting) and we imbibe them into Spectralite. It's the material that imbues the lens with the speedy response rate. Spectralite was redesigned to create "spaces" between the polymers for the chromaphores to expand into when they react (darken), which essentially makes the photochromic response more efficent (because the molecules find it easier to react in a material that was designed to house them in both clear and dark states). So lenses get darker faster, and the lifetime is improved because the photochromic molecules are chemically matched with the lens material to avoid degredation.

Best regards,
Darryl
Technical Marketing,
SOLA Optical

[Pete Hanlin]

If I order Quantum Transitions(r) in Spectralite, do I necessarily receive the Velocity(tm) lens- or are there seperate products?

When you say Spectralite was redesigned, do you mean the actual composition of the material was changed? I can't imagine how you would create "spaces" in the lens without changing the chemical compostion. Also, does your answer imply that part of the degredation process of Transitions concerns the fact that the chromaphores don't have the proper room needed for expansion? Would that also imply that polycarb is a good material for Transitions (since it is softer and thus theorhetically more pliable)?

Thanks for the useful info. I always get to increase my vocabulary when I read your posts (today's new word is chromaphores)!

Pete
PS- Thanks for the web site info, Jo. I'm including the web address in our newsletter so patients can look up additional info if they so desire.

[Darryl Meister]

Hi Pete,

Right now, I believe that we are making some lens designs in Velocity and others in Spectralite Transitions. Velocity is our proprietary version of Transitions Quantum on Spectralite products. (If you have a particular product in mind I can check for you.) I believe that we will eventually make all Spectralite designs in Velocity (if I'm not mistaken).

The Velocity/Transitions dyes can not be imbibed into polycarbonate -- they are imbibed into the coating on top of the lens substrate itself. Although polycarbonate isn't as highly cross-linked as thermosetting materials -- like hard resin and Spectralite -- there is a bit more to it than that for imbibing lenses with Transitions.

"Redesigning" a material like Spectralite can involve anything from changing certain chemical additives to using a different hard coating to adjusting the curing cycle of the process (the degree of cure, combination of thermal and UV cycles, etcetera).

You'll have to thank Bernadette for "chromaphore" -- she is a physicist, after all. ;) You might also see the Transitions photochromic process referred to as "photoisomerization."

If you want to e-mail me your mailing address, I'll ship off the collaterbal pieces and Q&A, which should answer many of these questions.

Best regards,
Darryl