Darryl great article in 20/20

**HarryChiling** · 10-11-2008, 11:41 AM

Darryl,

I got to say the article you have in this months issue of 20/20 is top notch info. I enjoyed it very much and thought it was chock full of information and did a great job of explaining progressives and their designs. I like dthe comparisons in the begining to show the slight differences between the progressives on the various combinations fo surfaces.

**Barry Santini** · 10-11-2008, 12:13 PM

Interesting, Harry. I sent Darryl a PM saying the same thing!

Barry

**HarryChiling** · 10-11-2008, 12:18 PM

Originally Posted by Barry Santini

Interesting, Harry. I sent Darryl a PM saying the same thing!

Barry

Some things were meant to be shared with everyone. ;):cheers:

**nickrock** · 10-11-2008, 04:31 PM

Was this in the September or Oct. issue?

**HarryChiling** · 10-11-2008, 04:50 PM

Oct. I think Sept. was Barry.

**Steve Machol** · 10-11-2008, 05:36 PM

I would expect nothing less from Darryl. He really is one of the great minds in Ophthalmic Optics today.

**Darryl Meister** · 10-13-2008, 12:55 PM

Thanks, Guys. I appreciate the positive feedback.

**rolandclaur** · 10-13-2008, 11:52 PM

Can anyone post the link to the article. I went to the website but couldn't find any info.. Maybe its too early.. Thanks

**Fezz** · 10-14-2008, 01:22 PM

Great job!

Thanks for sharing your knowledge with us!

:cheers::cheers::cheers:

October issue:

www.2020mag.com

**sharpstick777** · 10-24-2008, 09:00 PM

one of the best articles on freeforms. I had my entire staff read it (yea the eyes rolled through the back of their head).

Sharpstick

**Memoir** · 11-07-2008, 02:52 AM

"Tech Brief on Optical Optimization" by Darryl Meister, ABOM

For those people who missed out on, or couldn't get their hands on 20/20 USA October (like myself and a few others across the pacific!) - I've managed to source a .pdf of the article by Darryl courtesy of Carl Zeiss' marketing department.. if anyone would like a copy send me an email :)

regards,

-Memoir.

**Darryl Meister** · 11-07-2008, 08:35 AM

"Tech Brief on Optical Optimization"

That's actually a technical bulletin I wrote a few years ago. You can download it from OptiBoard Here. The 20/20 article describes the different types of free-form lenses that are currently available, the optical differences between them, the forms of customization that are available, etcetera.

**drk** · 11-07-2008, 02:02 PM

Points I found interesting:

1. No, the "keyhole effect" from a front surface progressive design isn't that big a deal. I couldn't imagine a 1.5-mm-thick "door" could make that much of a difference. Thank you.

2. That overall the placement of the add is not that big a deal. I guess Shamir or Seiko would howl and whine over that. But I prefer that it doesn't make a difference.

3. Reinforces the point Darryl has been communicating that it's all about "optimization for a sample size" and not some new "super progressive". Whereas some in the sample will have a LOT better vision, some in the sample will have the SAME vision with customized progressives. (Trick is, who is going to invest the time or effort to find out which type of subject is sitting in your chair?)

4. Indirectly and probably unintentionally throws a little mud on the Sheedy methodology. Yeah, old subject, but I'm just sayin'.

5. The mother lode! If I understood it properly, a reference (however cryptic) to optical aberrations causing an inadvertent translocation of the clear zones in a progressive. In other words, my "mystery pain-in-the-@$$" may have an explanation: that patient who, for some heretofore unknown reason sees better through their near zone with a head turn.

Some have dealt with this only marginally succesfully by measuring near p.d., plugging in an assumed inset, and ordering compensated distance p.d.s. I've dealt with it with a more empirical ad hoc millimeter or two p.d. adjustment. But now if we simply optimize, the issue will go away.

I have a case presentation that demonstrates this phenomenon. Suffice it to say that I banged my head on the wall until I went the customized progressive route.

6. My, my we shouldn't be wrapping standardized progressives for sunwear. The nice little graphic shows what we've come to understand: it narrows down the clear zones dramatically. It's a crapshoot.

**HarryChiling** · 11-07-2008, 04:39 PM

Originally Posted by drk

3. Reinforces the point Darryl has been communicating that it's all about "optimization for a sample size" and not some new "super progressive". Whereas some in the sample will have a LOT better vision, some in the sample will have the SAME vision with customized progressives. (Trick is, who is going to invest the time or effort to find out which type of subject is sitting in your chair?)

4. Indirectly and probably unintentionally throws a little mud on the Sheedy methodology. Yeah, old subject, but I'm just sayin'.

3) Every progressive lens is optimized, the difference is that in semi finished lenses each curve will have one truly optimized Rx and the rest are within tolerance that the manufacturer has chosen. I personally think it should be available data which Rx is the optimal Rx fro which blank, I guess if you really wanted you could split the range of a blank and the middle would more than likely be the optimal Rx for that lens blank.

4) I am curious how you drew that parralel? Even with the new FF designs out right now their are still some that like on progressive over another for whatever reason and their are still non-adapts, so we haven't reached the promise land yet if their even exists one. Every company has stretched the truth to some degree and the article Darryl wrote helped shed some light on the topic but I think it would be a stretch to say that Sheedys methodology has mud on it, it is an objective part of rateing a progressive, and manufacturers coudl very easily make that data available but they don't which makes me suspicious but that's just my nature. Manufacturers tend to put more stock in user trials which are subjective making it very difficult to make comparisons.

**Fezz** · 11-07-2008, 06:18 PM

Originally Posted by drk

5. The mother lode! If I understood it properly, a reference (however cryptic) to optical aberrations causing an inadvertent translocation of the clear zones in a progressive. In other words, my "mystery pain-in-the-@$$" may have an explanation: that patient who, for some heretofore unknown reason sees better through their near zone with a head turn.

Some have dealt with this only marginally succesfully by measuring near p.d., plugging in an assumed inset, and ordering compensated distance p.d.s. I've dealt with it with a more empirical ad hoc millimeter or two p.d. adjustment. But now if we simply optimize, the issue will go away.

I have a case presentation that demonstrates this phenomenon. Suffice it to say that I banged my head on the wall until I went the customized progressive route.

Hey Doc,

Care to elaborate in a new thread?

**drk** · 11-09-2008, 10:27 PM

Harry: I mean that Darryl mentioned, during the lens wrap discussion I believe, that lensometer performance standards don't equal "as worn" performance standards. He said as much on here, when "grain-of-salting" the Sheedy methodology. I don't think he was being nasty or anything, just stating it has it's limits:

"Traditional progressive lenses are often designed to exhibit the specified optical performance only when measured using a focimeter, such as a lensometer..."

But yeah, like you I'm for "transparency" and against hype-ola. There's no reason however that you couldn't do the "Harry C" report with five progressives and, say, 25 well-placed data points with the simple method Sheedy used. For manufacturers to release that data doesn't make a lot of sense, especially if, as you point out, correlation to patient satisfaction is tenuous.

Fezz: I'll get on it. As a beginning:

"The optical effects of lens aberrations are exacerbated in progressive lenses...Lens aberrations can also cause the viewing zones of a progressive to become distorted from their ideal location as certain regions of unwanted astigmatism become more blurred while other regions actually become clearer. This distortion of the central viewing zones disrupts binocular vision through the lenses by moving the “sweet spots” of the lens."

**Barry Santini** · 11-10-2008, 06:57 AM

I'm not sure that Darryl's article included another contributung factor to overall progressive perfomance/satisfaction: Namely, that incomplete or inaccuratelty-corrected wearer astigmatism can also sum-up with both the combined effects of oblique & surface astigmatism of progressives to *further* reduce, shift, or otherwise affect perceived zonal limits. In a presentation I attended years ago, A Zeiss lens specialist referred to the specific symptom of this situation, which he called "hot-spotting".
"Hot-spotting" is where the wearer indicates that things are sharp when they hold their head a particular way (usually in the DV portion), but a slight movement then blurs it (or visa-versa). When I hear or describe this wearer symptom, it *always* ends up with a subsequent re-refraction that reveals incomplete (power or axis) or uncorrected astigmatism (0.25 to 0.50D).

Spherical-equivalents may be ok for those SV, Bif, and OTC wearers (if cost is the bottom line), BUT NEVER FOR OPTIMAL VISION IN PROGRESSIVE LENSES!

Thanks for listening!

Barry

**drk** · 11-10-2008, 08:59 AM

good pernt

**Darryl Meister** · 11-10-2008, 09:18 AM

I'm not sure that Darryl's article included another contributung factor to overall progressive perfomance/satisfaction: Namely, that incomplete or inaccuratelty-corrected wearer astigmatism can also sum-up with both the combined effects of oblique & surface astigmatism of progressives to *further* reduce, shift, or otherwise affect perceived zonal limits.

Nah, this type of error would've been outside the scope of this particular article. I did cover this topic in that progressive lens dispensing presentation I have in the File Downloads forum though.