Question about back surfaced SV blank progressives

[pezfaerie]

We have been having a discussion with some of our older Opticians (40+years in Optics) and lately they are angry about the amount of distortion/abberation that the new backside digitally surfaced SV blank lenses have at the fitting cross. If they move the lens "slightly" side to side the myers jump or become blurry. They said that if the lens is made from a SV blank, that anything at and above the fitting cross from one side of the lens to the other (horizontally/periph) the myers should be clear.
The only way I could think to explain why they are not 100% clear SV blank or not, is that the progressive design had to be put on the lens and there is still a corridor where the rx has to be manipulated to make that corridor clear for POW. Is that correct? They had pulled out a comfort2 lens to show how much "clearer" the myers were when moved. Yet when I look through and compare both the comfort and the digitally surfaced lens, the meyers on the comfot get distored at the very edges of the verification circle ( ) and on the digital lens its right outside of the circle, which tells me that the digital lens has just barely wider areas at the top.
Any other ideas how to explain that the digital lenses are a step up and not just all marketing hype? So far the public feed back has been fantastic. But the older Opticians feel like they are over charging for a horrible lens design.

[AngeHamm]

I guess it's not an option to mention that patients aren't looking through their eyeglasses through a lensometer.

[pezfaerie]

I guess it's not an option to mention that patients aren't looking through their eyeglasses through a lensometer.

LOL. I tried to say that in a round about way as to not sound snarky. But even in saying that, it was brought to my attention that the lensometer is what has been used to measure/verify power "forever" in the industry and if they were checking a conventional lens vs the digital pals the new ones would be rejected for abberrations. Granted, its me that does the verification and I have studied up on the newer technology for progressives (not that I am 100% on every PAL topic) and I understand what's passable and not. The lenses here get doubled checked after edging and once before dispense by different people and this is how the whole topic got started.
I just don't want the owner to feel that he is selling an inferior product because its new technology and supposed to be better. And I suck at explaining things

[Robert Martellaro]

We have been having a discussion with some of our older Opticians (40+years in Optics) and lately they are angry about the amount of distortion/abberation that the new backside digitally surfaced SV blank lenses have at the fitting cross. If they move the lens "slightly" side to side the myers jump or become blurry. They said that if the lens is made from a SV blank, that anything at and above the fitting cross from one side of the lens to the other (horizontally/periph) the myers should be clear.

That's due to the PAL design; some designs put more of the unwanted astigmatism into the distance periphery, other designs have less.

[pezfaerie]

That's due to the PAL design; some designs put more of the unwanted astigmatism into the distance periphery, other designs have less.

Thank you

[Paul Smith LDO]

The construct of the compensated FF design with POW measurements is to clean up image displacement thru centrad; we should see power changes across the lateral surface of the distance quadrant. The design of the FF w/o POW just utilizes the manufacturers pre calculated default.

[MakeOptics]

We have been having a discussion with some of our older Opticians (40+years in Optics) and lately they are angry about the amount of distortion/abberation that the new backside digitally surfaced SV blank lenses have at the fitting cross. If they move the lens "slightly" side to side the myers jump or become blurry. They said that if the lens is made from a SV blank, that anything at and above the fitting cross from one side of the lens to the other (horizontally/periph) the myers should be clear.
The only way I could think to explain why they are not 100% clear SV blank or not, is that the progressive design had to be put on the lens and there is still a corridor where the rx has to be manipulated to make that corridor clear for POW. Is that correct? They had pulled out a comfort2 lens to show how much "clearer" the myers were when moved. Yet when I look through and compare both the comfort and the digitally surfaced lens, the meyers on the comfot get distored at the very edges of the verification circle ( ) and on the digital lens its right outside of the circle, which tells me that the digital lens has just barely wider areas at the top.
Any other ideas how to explain that the digital lenses are a step up and not just all marketing hype? So far the public feed back has been fantastic. But the older Opticians feel like they are over charging for a horrible lens design.

Bite your tongue and wait for them to retire! More often than not, their is nothing you can teach them when they are no longer receptive, it's a cancer try not to catch it.

[uncut]

Pez:

Some of the quality of lens surface issues they note are not necessarily software, or "science" planned..............it's just poor quality finishing, often hidden by layers of AR or hard coat material..........older eyes are trained to spot surface defects often deemed to bee A"acceptable " by the young egemecated uns.

The "wow factor " you refer to as public feedback can be the new rx, less scratched and upgraded to better quality raw material and frame fit.........not the lens technology.

In a "reverse engineering way" you may eventually experience a person proclaiming that they saw better through their old school glasses from 10 years ago(insert young un eyeroll here)

What the veterans are noticing, unlike the mediocritics, is the quality drop.

[Wes]

Pez:

Some of the quality of lens surface issues they note are not necessarily software, or "science" planned..............it's just poor quality finishing, often hidden by layers of AR or hard coat material..........older eyes are trained to spot surface defects often deemed to bee A"acceptable " by the young egemecated uns.

The "wow factor " you refer to as public feedback can be the new rx, less scratched and upgraded to better quality raw material and frame fit.........not the lens technology.

In a "reverse engineering way" you may eventually experience a person proclaiming that they saw better through their old school glasses from 10 years ago(insert young un eyeroll here)

What the veterans are noticing, unlike the mediocritics, is the quality drop.

True enough. However, this isn't a failure of free-form digital designs. It's due to poor quality control in cut-to-polish operations. While free-form digital designs use cut-to-polish manufacturing, many labs use the same equipment and process to run conventional designs as well. Here, the process creates the poor surface, not the design.

FWIW, I don't think this is what the OP is talking about.

Digital designs tend to have wider fields of view than conventional designs and back surfaced digital designs will appear to the wearer as having a wider field of view than digitally created front surface molds, because they are marginally closer to the wearer's eye.

I think you should probably follow MakeOptics' advice on this one.

[Craig]

When in doubt: Follow the advice of MakeOptics and Wes, you can't go wrong but may gain thinking of a new way to look at things. That is what I do.
Craig

[jpways]

I have to ask because it is related to a problem we're noticing. Are these Essilor SV blanks because in the past 6-9 months 60-70% of our Shamir digital polycarbonate jobs and 20% of our stock SV poly jobs have been coming in distorted without the lenses being cut too big (I've taken some the lenses out of the frame). And this has been work from 3 different labs (Central One Optical, Three Rivers Optical, and Luzerne Optical) and I've seen similar crap rates from all three labs. And after the third or fourth time (sometimes fifth) the lab is starting to get annoyed with my rejection of otherwise good jobs. So the only conclusion I can make is that it's the blanks Essilor is putting out.

[Craig]

I just had an issue with digital surfacing at my lab and it was a generator specification that had gotten changed; it was causing weird optics and numbers at verification.
They got if fixed asap and did not deny or argue with me. They thanked me.

[uncut]

Bite your tongue and wait for them to retire! More often than not, their is nothing you can teach them when they are no longer receptive, it's a cancer try not to catch it.

A bit of a harsh piece of advice........and very discriminatory as well, doncha think?