Current state of the art in photochromics?

[EyeSpecSo]

Speaking as an eye care consumer, and not a very knowledgable one at that, I'd like to know what's currently available in photochromic materials for progressive lenses correcting for presbyopia. Has anything come along that improves on my current Transistions NG?

The catch is that I'm most concerned with a single issue. I want the widest possible light-to-dark range at high temperatures, like 90F.

Of course, I'd like it if the lenses fade rapidly when I go indoors, but I'm not willing to sacrifice high-temperature darkening to get that benefit. I tried some "Kodak Instashades" last year, but found that trade-off entirely unsatisfactory. In fact, I'd be willing to accept slower fading if I could get better high-temperature absorption than my current lenses.

And yes, I'd like lenses that respond to visible light, but only if they darken well in the heat of the summer.

So, for now, I'm only interested in lenses that get good and dark when it's hot. Those other issues, which are very important to some people, are irrelevant to me.

I would be grateful for any leads.

And while I'm asking, what's the current state of AR coatings? My current lenses have a lab coating, which was only identified to me as Satin. It was suggested at the time that its performance might be similar to that of Alize, but I find it just as difficult to keep clean as all my previous AR coatings.

I've seen some references to more advanced coatings that build on the advantages of Alize, but have seen no names. What should I investigate.

Thanks for your help. The advice I got last year helped me communicate my preferences to my ECP, and I think we have a better relationship now. I prefer to do business with someone who's local, and to deal with the same people year after year. I'm not going to lowball them on the price, but I do want to get glasses that serve my needs.

[chip anderson]

Photogray

[Jacqui]

Deffinately Photogray

[Happylady]

Deffinately Photogray

Why are you recommending this? Photogray is glass and is heavy. It also doesn't lighten as well as the plastic lenses, in time the lenses take on a fairly dark indoor tint.

I have used the Thin and Dark glass lens with good success for some patients.

[Andrew Weiss]

Photogray if you're willing to live with glass lenses. If you want a form of plastic, try either Rodenstock's Colormatic (if you can find it) or SunSensors. But be aware that even those require a lot more UV than visible light and won't darken as much as the Photogray will.

[Happylady]

I have not had good experiences with SunSensors. They lighten to a odd color indoors and don't seem to get as dark as Transtions outside. We had an employee get a pair with an AR coat and the really didn't darken well with the AR. This was several years ago, though, and perhaps they fixed that problem.

Why Photogray over Thin and Dark?

[Jim Schafer]

Using a 2mm CT plano lenses, at 35°c/95°f and 30 minutes exposure, a Photogray (PGX) will darken to 44% transmission , a Thin and Dark will darken to 29%.
Of course with a heavier Rx (thicker lens) PGX will get darker, both indoors and outside. That is why some of you may think PGX is the darker product.

Transitions Next Generation will darken to 27%, Transitions V will darken to 33%. Velocity Transitions will darken to 34%

In perspective, the old Transitions III (1998-2001) darkened to 41% at 95°.

The other organic non Transitions lenses will darken 37% to 61% Transmission.

Your current Next Generation lens is by far the best performer.

stay cool!
regards,
Jim

[Cherry Optical]

Has anyone run tests on the Kodak Instashades product? I would be interested to know how it holds up in high temps.

Interestingly enough we had three phone call last week here in NE Wisconsin, complaining of Transitions that "don't work anymore." We explained how the heat can play havoc with these lenses.... it was 90+ with very high humidity... hazzy skies.

Adam

[EyeSpecSo]

Thanks for all responses.

Jim, you steered me in the right direction last year, and I'll probably stick with Transitions NG.

However, I am interested in Happylady's mention of Thin and Dark. I have read that this material is not suitable for prescriptions for presbyopia. Has anyone found it satisfactory?

I'm curious about how Thin and Dark lenses would perform in one particular situation: within two hours after sunrise or before sunset, when the UV index is very low, but the sun is near the horizon and in my eyes. At temperatures below 60F or so, my Transitions darken adequately for this situation, but above 80, they give me no comfort.

Would any photochromic material perform well in that situation?

Adam, while I can't claim scientific accuracy, I had a pair of Instashades last year, for about one week, and I compared them with my previous lenses, using readily available equipment for measuring light levels. The old lenses were Transitions 3s, which by then were showing some fatigue. Using a camera that metered in half-stop increments, after ten minutes exposure at 89F, I could not consistently find any darkening in the Instashades, although they sometimes caused a half-stop drop in light level, so I estimated their transmittance as greater than 75%. The T3s consistently caused a full stop drop in light level, so I estimated their transmittance as 50%, but with a very wide margin of error.

At 79F, both lenses did much better. I was using a camera with 1/3-stop metering by then, and was able to estimate the Instashades at 40% after ten minutes, with the T3s at 32%.

Again, I make no claims for scientific accuracy. I had very little control over conditions, and so had to work with the conditions that existed. Further, my measuring systems were lacking in precision and not necessarily calibrated to any outside standard. But I'm rather confident that in each case, the old T3s did better than the Instashades.

[chip anderson]

Do you find an empathetic relationship with "Monk?"

[edKENdance]

Chip you're such a bas/tard:cheers:

[EyeSpecSo]

Do you find an empathetic relationship with "Monk?"

I puzzled over this. What could my musical tastes have to do with it? :)

Google to the rescue: I see now that there is a TV series called "Monk", about a detective who is afflicted with an immobilising obsessive/compulsive disorder. So now I think I understand: the implication is that anyone who would go to the trouble to test his own glasses must be similarly deranged.

I guess that's true, too. Maybe most people don't really mind being subjected to a hard sell for a product they don't want. And when they find the product is unsatisfactory, they wouldn't feel any need to quantify its shortcomings.

So it must be true that I'm abnormal this way. I'll just have to learn to live with it.

But I thought that if you wanted to compare my exploits to a fictional character on TV, MacGyver might be a better choice.... :)