verifying progressives ...oh my!

[pseudonym]

Hi, I'll be a second year student in the fall and have wormed my way into the back of a shop where they are letting me observe repairs and look at donated specs all I want. It's a sweet deal for me but I don't want to spoil it by asking a lot of questions while they are trying to run a shop.

I'm getting ok with bifocals, but these progressives are a whole nother thing. I'm getting the Rx ok, but I can't figure out how to verify the add. Yesterday I found out that they just look for the number etched on the lens and write that down as the add. I've read every tutorial I can get my hands on and they all say to turn the glasses around ocular side facing the OP and place the near verification circle over the aperture, get the sphere reading in the near zone and take the difference between that and the sphere reading in the distance.

Problem: The sphere reading in both zones always seems to be wavy or broken up. I'm not getting what the etched number says in any case. You guys must have looked at a few of these, right? So what am I doing wrong??

[Jacqui]

Try changing the axis on the lensometer by 90 degrees. You should be able to figure out why :D

[chip anderson]

While not 100% reliable (but close) most progressives will have "invisible" marks on the lens indicating the add power. Often difficult and sometimes impossible to see, but they are usually there and can usually be seen in the right light, at the right angle. Sometimes a head loop helps.

Also note they are often abreviated like: 2.5, or 2 or 1.7 instead of the full number. Usually located below one of the trademarks which are also "invisible."

Chip

[pseudonym]

Try changing the axis on the lensometer by 90 degrees. You should be able to figure out why :D

Believe me, the wheel may fall off from the many directions I've turned it. I get wavy sphere lines in all meridians. I've also repositioned the glasses numerous times in front of the aperture to try to get the lines to appear straight. Once in a while I get a pair of glasses that the sphere lines come in straight, but not often.

I realize that opticians in the field merely note the etched number and write it down as the ADD, but what is the reason for the "near verification circle" if no one actually uses it to verify that the near power matches the etched number?

I've been told that the state boards will require us to verify the ADD through the lensometer. Is that right? If so, I need to figure out what I'm doing wrong. (Yes, I do match the logo on the lens to the lens chart to find out where to mark the lens. No problems there.)

[obxeyeguy]

You are indeed right, flip them around, and read as low as you possible can in the glasses. The mires are still somewhat out of focus, but should be close. Neutralizing any progressive is totally a guess on the add, in my opinion. Another reason the state boards are out of touch with the industry, as it is inscribed on the lens.:hammer:

[hcjilson]

Another reason the state boards are out of touch with the industry, as it is inscribed on the lens.:hammer:

That statement was easy to type out, but difficult, if not impossible, to substantiate.

To the best of my knowledge, regulatory boards are composed of actively engaged opticians. Also to the best of my knowledge, practical exams allow the use of the etched number to determine the add.With all due respect, what leads you to the conclusion that state boards are out of touch with the industry? Quite the opposite, board members are usually on the cutting edge because they are often asked to make judgement calls on procedures, materials, techniques, and competence.You really can't do that if you are out of touch with the industry.

Just because a board acts in a way that is not in agreement with some in practice, does not mean they are out of touch with the industry. Just because a board does not move on something quickly enough to suit some does not mean they are out of touch with the industry. Please keep in mind that boards are governed by the statutes that created them. Most originally were written 50 or more years ago and to change them, which is necessary due to advances in technology, requires a lot of time and patience. Boards are probably more in touch with the industry than those who practice within their jurisdiction. You can take that to the bank.

[pseudonym]

You are indeed right :hammer:

Words I never tire of hearing, thank you.

But the rest of what I'm reading brings up an interesting question. Why does the near viewing verification circle exist if no one ever seems to use it?

[hcjilson]

Same reason Sir Edmund Hillary climbed Mt Everest......................Because it's there! :):)

[obxeyeguy]

That statement was easy to type out, but difficult, if not impossible, to substantiate.

To the best of my knowledge, regulatory boards are composed of actively engaged opticians. Also to the best of my knowledge, practical exams allow the use of the etched number to determine the add.With all due respect, what leads you to the conclusion that state boards are out of touch with the industry? Quite the opposite, board members are usually on the cutting edge because they are often asked to make judgement calls on procedures, materials, techniques, and competence.You really can't do that if you are out of touch with the industry.

Just because a board acts in a way that is not in agreement with some in practice, does not mean they are out of touch with the industry. Just because a board does not move on something quickly enough to suit some does not mean they are out of touch with the industry. Please keep in mind that boards are governed by the statutes that created them. Most originally were written 50 or more years ago and to change them, which is necessary due to advances in technology, requires a lot of time and patience. Boards are probably more in touch with the industry than those who practice within their jurisdiction. You can take that to the bank.

Harry, sorry I hit your buttons on the state boards, as I know you have done a great deal for them, and it is in fact appreciated. Now, to the point. The lens is engraved for a reason, right? I have seen Doctors only use the engraved numbers to neutrilize, as the adds on most progressives do not in fact read true, even to the most experienced opticians.

Have we in fact "dumbed" down the industry by putting those there? I don't have the answer, but the fact that they are there, and I for one use them. Making a student not use them in my opinion is outdated, and counterproductive to the industry. That's where the "out of touch" comes in, as the state boards do not move anywhere as quick as this industry changes, and in many cases, not at all.

If I neutrilize a Rx to duplicate on a progressive, I do in fact use the engraved number, but I also do read it.

Sorry to ruffle your feathers, but its what I think.

[hcjilson]

Have we in fact "dumbed" down the industry by putting those there? I don't have the answer, but the fact that they are there, and I for one use them. Making a student not use them in my opinion is outdated, and counterproductive to the industry. That's where the "out of touch" comes in, as the state boards do not move anywhere as quick as this industry changes, and in many cases, not at all.

I don't think you can accuse a board for being out of touch with the industry because they don't move fast.I hope my explanation of why that is the case is sufficient. The fact that a board requires the neutralization of a progressive lens is proof that they have at least recognized the importance of the etched markings. I haven't seen a practical that disallows using what has already been given on the lens itself, AND YET...I have seen the results of those taking the practical, getting that question wrong, when all they had to do was read the markings. Anyway no hard feelings,..... boards try to do the best they can.

[pseudonym]

Obviously, I don't have a dog in this fight. I'm only too happy enough to learn whatever NCLE wants me to learn. The near verification circle is there for a reason, which I suspect is to verify near power.

There are numerous tutorials online that describe how to verify progressives and they all have one fault. They make it sound easy. Easy it is not. I have lensometer eye from the past week of trying to teach myself how to do it.

Thanks for the confirmation that I am trying to learn something that is, indeed, so difficult that almost no one else bothers except someone who is studying for the boards and maybe obxeyeguy. Peace out.

[pseudonym]

"The NCLE doesn't care a hoot about verification circles, they are contact lens examiners! You may be able to neutralize the add power on a progressive lens, but you still have something to learn!"

Meant to write the acronym for the NC State Board of Opticianry whatever it is. And if you have been reading my posts instead of trying to be clever, you would have noticed that I do not know how to neutralize a progressive lens. At this point, I am still trying to learn.

The verification circles are there because they are there? Well, that's helpful. Thanks so much.

[Laurie]

Hello,

I think it is great that you actually want to become competent in neutralizing and verifying for yourself, and not just trusting the engraved notations.

And, you have uncovered one of the industry's dirty little secrets...an overwhelming amount of PAL designs do not even make it to 100 percent of the add power once edged...!

Good to know which ones are which, and you will soon learn this as you neutralize additional pals from different manufactures.

One tip:

from the opposite surface (Convex side against the lens stop, temples toward you), go to the highest point possible for the first sphere reading, and the lowest point possible for the nearpoint reading. It is OK if the sphere lines are slightly wavy...you can still get the reading. And, Jacqui was correct about the axis dial...make sure you are in the same cylinder (plus or minus cylinder) readings both time.

Finally, compare the two readings from the same surface.

: )

Laurie

[Chris Ryser]

And, you have uncovered one of the industry's dirty little secrets...an overwhelming amount of PAL designs do not even make it to 100 percent of the add power once edged...!

Congratulations Laurie...............so far none of the others has thought of it.

Those lenses with not enough depth have the edge at the edge of the full reading power, which actually should give a clear picture in the lensometer.............but if is not there you are still in the progressive area.

Problem solved, get a lens with lots of depth and you will find it.

[HarryChiling]

Obviously, I don't have a dog in this fight. I'm only too happy enough to learn whatever NCLE wants me to learn. The near verification circle is there for a reason, which I suspect is to verify near power.

There are numerous tutorials online that describe how to verify progressives and they all have one fault. They make it sound easy. Easy it is not. I have lensometer eye from the past week of trying to teach myself how to do it.

Thanks for the confirmation that I am trying to learn something that is, indeed, so difficult that almost no one else bothers except someone who is studying for the boards and maybe obxeyeguy. Peace out.

I've heard something like 50% of people fail the lensometer portion. I would ignore bad advice about not checking properly, especially on the boards.

Everyone has mentioned using the difference between the front vertex powers for the add, I would also add (no pun intended) that you should be marking each progressive with their mask, or marker using the proper cut out chart. You can find them from our resident lens guru, lensguru (www.thelensguru.com) it's not to difficult to memorize the most common ones. Good luck.

[hcjilson]

Quick question for all you guru's out there....has anyone tried to mark up a lens with Crizal Alize Avance yet? I had occasion to do that last week and was unable to find anything that stuck. I wound up using a wax crayon but that was really unsat. Any brighter ideas??

[HarryChiling]

Quick question for all you guru's out there....has anyone tried to mark up a lens with Crizal Alize Avance yet? I had occasion to do that last week and was unable to find anything that stuck. I wound up using a wax crayon but that was really unsat. Any brighter ideas??

Staedtler lumocolor permanent markers do the trick.

[hipoptical]

Hello,

And, you have uncovered one of the industry's dirty little secrets...an overwhelming amount of PAL designs do not even make it to 100 percent of the add power once edged...!

Though this is true, you will find upon further examination, that most PALs do not reach 100% even AT the verification circle. Thus, the reason "pseudonym" cannot truly verify the lenses, and the reason the verification circle is not used are, in fact, the same. We have come to trust that a lens that is molded will be molded correctly, and there is nothing that one can do to affect or change the outcome. This problem becomes even greater as labs begin to make digital lenses. Some will be laser engraved, some will not be. Some will have variable corridors (length, width, and/or inset) and some will not. It is impossible to then verify these type properly without mapping it, marking it, and verifying on the wearer. That's too much work, so most will:
1. Opt for traditional lenses because it "says so on the laser marks"
2. Trust the lab that the product was, in fact, produced correctly

[obxeyeguy]

Staedtler lumocolor permanent markers do the trick.

I find that the uniPosca paint type pen works better on avance. The lunocolor works good for me on the regular crizal and alize.

[Laurie]

Hipoptical makes a good point...

Though this is true, you will find upon further examination, that most PALs do not reach 100% even AT the verification circle.

...we could trust the markings or trust the lab,

....or...we could only dispense PALs that promise 100 percent of the Add. And, verify it with our lensometer to see that it is true. If not, send it back.

This, of course, will not help for board prep, as the candidates must neutralize whatever lens is presented. I am making the point more for dispensing in general, and choosing lenses that provide the full add.

: )

Laurie

[pseudonym]

Laurie wrote:

And, you have uncovered one of the industry's dirty little secrets...an overwhelming amount of PAL designs do not even make it to 100 percent of the add power once edged...!

I wish I could say "Elementary, my dear Watson" but actually I didn't realize I'd stumbled onto anything of significance. All I know is I'm not getting the correct ADD power when I position the aperture over the area labelled "near verification circle" on the template. Which makes me wonder if the circles are just useless decoration or what. I will go as low as I can in on the lens itself tomorrow and check my readings again- being careful to stay in the same cylinder for distance and near.

[pseudonym]

This problem becomes even greater as labs begin to make digital lenses. Some will be laser engraved, some will not be. Some will have variable corridors (length, width, and/or inset) and some will not. It is impossible to then verify these type properly without mapping it, marking it, and verifying on the wearer. That's too much work, so most will:
1. Opt for traditional lenses because it "says so on the laser marks"
2. Trust the lab that the product was, in fact, produced correctly

The second option is frightening considering that I saw a pair of glasses in the remake bin today that came in with a 91 pd. I asked if they would let me look at them in the lensometer, and sure enough I couldn't begin to get them centered.

New question: 91 pd is obviously wrong and it was even marked 91 pd on the lab ticket! Don't labs have some kind of parameter for pd's that would reject them outright before they ever reach the shop? Or at least have the parameter set at (say) 74 which is the largest pd I've personally seen that would flag them for a technician to check and possibly manually override in the case of giantesses and ogres?

[pseudonym]

I've heard something like 50% of people fail the lensometer portion. I would ignore bad advice about not checking properly, especially on the boards.

Everyone has mentioned using the difference between the front vertex powers for the add, I would also add (no pun intended) that you should be marking each progressive with their mask, or marker using the proper cut out chart. You can find them from our resident lens guru, lensguru (www.thelensguru.com) it's not to difficult to memorize the most common ones. Good luck.

Using the proper cutout chart isn't always possible with donated specs- some of these things are strictly disco bondage headgear. I've been told to use any 4mm template if I can't id the logo.

[chip anderson]

Geeze you guys, I would be happy if I could feel 100% confident of the PD, much less the power on PALS.

Chip

[obxeyeguy]

All I know is I'm not getting the correct ADD power when I position the aperture over the area labelled "near verification circle" on the template.

You are not getting the right power according to who? How are they reading the "correct" power? Lensometer or the engraved markings?