Does material affect how dark transitions get?

**Quantrill** · 10-20-2009, 09:31 AM

Is it true that hi-index transitions will get darker than poly? Would it get darker still with AR?

I wouldn't think that increased light transmission would necessarily make a lens get darker but apparently some people are convinced that a hi-index lens with AR will get darker than it's polycarbonate counterpart.

I'd appreciate any help you could offer.

**Jim Schafer** · 10-20-2009, 10:10 AM

Hello Quantrill,

No, all Transitions VI lenses have the same performance. It does not matter on the lens material.

Jim

**Quantrill** · 10-20-2009, 11:25 AM

Thanks for the fast response!

Much appreciated.

**MarcE** · 10-21-2009, 11:21 PM

And just to add about the AR - I think I recall that Jim has posted in the past that AR will NOT allow the Trans to get any darker. I guess the theory is that more light arrives to the magic Transitions crystals.

But you have to remember that more light is also traveling through the lens - so even if the Trans got darker, it's negated by the fact that vision should "Seem" about 10% brighter with AR on poly.

You can tell your commrades that the issue is now settled; because Jim Schafer is THE de facto expert in such matters.

**DragonLensmanWV** · 10-22-2009, 01:14 PM

Not only that but an AR will not increase the amount of light impacting the lens.

**Yeap** · 10-27-2009, 05:02 AM

i have understand that AR on the lens will not affect the performance of the transition as transition lens is not activated by the light amount that reach the lens.. But how about the UV treatment on the lens? will it affect the transition lens performance?

thank you..

**Jim Schafer** · 10-27-2009, 06:38 AM

i have understand that AR on the lens will not affect the performance of the transition as transition lens is not activated by the light amount that reach the lens.. But how about the UV treatment on the lens? will it affect the transition lens performance?

Yeap,
Transitions lenses and all other photochromic lenses are activated by light that reaches the lens surface. Most photochromic dyes are UV activated and others are also activated by visible light too (dyes used in DriveWear as an example, are activated by both UV and VL regions of the spectrum).

In the late 80's and early 90's most AR stacks for non mineral lenses had UV absorbing/blocking properties. The AR hindered or eliminated all photchromic activity of early Transitions lenses (Generation I and Transitions Plus).

By the mid 90's AR stacks and process had changed, the stack components no longer absorbed/blocked UV in the region needed to activate photochromic lenses. Transitions III and Transitions XTRActive were compatible with most premium AR brands of that time. Some may remember the Transitions AR Approved List for labs and coating centers that participated in screening of what AR brands did not hinder photochromic performance. AR and photochromic dye technology continue to improve through out the last 15 years. Something like 70% of all Transitions lenses dispensed are also AR lenses.

As far as UV treatments, never ever use one on a photochromic lens. There is a statement on Transitions lens packaging that has been there for almost 20 years.....

UV Coating of this lens will adversely affect the performance characteristics.

regards,
Jim