Automatic lensometers: the devil's own work or what?

[pseudonym]

I've been reading, re-reading, and re-re-reading a box of donated glasses for practice. For verification, I used an automatic lensometer which is kept under the sink in the doc's office. In all but three pair, the automatic lensometer got the same reading as the ordinary lensometer. Two of the three were just rounded differently but the last one was a complete mystery. It claimed there was a 0.25 cyl in a lens that was actually a sphere. When I aligned the glasses slightly different (but still centered), the cyl reading disappeared.

So tell me, what opinion do you have on automatic lensometers? Do you use them in your office? Do you hide them under the doc's sink? I'm curious.

[Barry Santini]

automated lensmeters w/ abbe value compensation and 0.001D precision are IMHO, absolutely essential today.

But, we still corroborate axis with our manual lensmeter. And we use the manaul model for marking OCs.

Barry

[pseudonym]

Do you read in quarter diopters or eighths? I had the machine set to quarter stops which led to the rounding discrepancies. Otherwise, the machine did a great job and did it fast.

[Wes]

When you say you aligned them differently, do you mean you induced tilt in the lens, removed the tilt, or moved the lens over a bit. Tilt, wrap, pantoscopic, whatever you want to call it, will induce cylinder. (Hold any spherical lens, higher powers induce more, in front of your eye. Look at a pic on the wall and tilt the lens. Voila, induced cylinder. There's a formula to calculate how much on opticampus.)
If, however, you only moved the lens a tad right, left, up, or down, perhaps the lens had a slight wave in it.
Autolensmeters have their place, but I wouldn't be without my trusty B&L 70.
Wes

[Fezz]

automated lensmeters w/ abbe value compensation and 0.001D precision are IMHO, absolutely essential today.

But, we still corroborate axis with our manual lensmeter. And we use the manaul model for marking OCs.

Barry

What models or brands to you suggest?

[Fezz]

Do you read in quarter diopters or eighths?

If checking *free-form* or *digitally processed* lenses, do we accept what you are questioning.................or a much higher accuracy?

[Barry Santini]

Autolensmeters have their place, but I wouldn't be without my trusty B&L 70.
Wes

Interesting...

I feel just the opposite: On a deserted island (w/electricity of course), I wouldn't be without my Zeiss-Humphrey lab 360 automated lensmeter (now discontinued, I'm told).

Barry

[Wes]

Interesting...

I feel just the opposite: On a deserted island (w/electricity of course), I wouldn't be without my Zeiss-Humphrey lab 360 automated lensmeter (now discontinued, I'm told).

Barry

Barry, I was about to give that as my answer to Fezz' question.
Wes

[Fezz]

Barry,

I am certainly not in your intellectual league, but I am trying to come along for the ride!

* I wonder what automatic lensometers that labs are using?
* I wonder what auto lensometer that the labs that are pushing *free-form* and *digital* processing are using to check their work.
* I wonder what those labs are using to calibrate those lensometers?
* I wonder if we all should *believe* what those labs send as a readout for verification of lenses from those lensometers?

[pseudonym]

If checking *free-form* or *digitally processed* lenses, do we accept what you are questioning.................or a much higher accuracy?

Not sure I understand your response. The glasses in the donate bin were moldy oldies- many bifocals and photograys. If they came into focus at an eighth stop, I rounded to give more minus in the sphere.

[pseudonym]

When you say you aligned them differently, do you mean you induced tilt in the lens, removed the tilt, or moved the lens over a bit. Tilt, wrap, pantoscopic, whatever you want to call it, will induce cylinder. (Hold any spherical lens, higher powers induce more, in front of your eye. Look at a pic on the wall and tilt the lens. Voila, induced cylinder. There's a formula to calculate how much on opticampus.)
If, however, you only moved the lens a tad right, left, up, or down, perhaps the lens had a slight wave in it.
Autolensmeters have their place, but I wouldn't be without my trusty B&L 70.
Wes

The frame was locked down but there were 2-3 millimeters of play where the window continually read that the lens was aligned. Within this area, there were two slightly different readings for this particular pair of glasses.

[chip anderson]

Automated lensometers are designed to allow people educated during the "dumbing down of America" to be employed in the optical office. They serve their pupose. They also furnish computer print outs that impress those who question the accuracy of the person using a manual lensometer, they serve their purpose. Ralph Drew once said: "There's nothing that impresses a doctor more than an computer print out from a lensometer."
Manual lensometers were designed to be used by Opticians. They do this well.

Chip

[Wes]

Barry,

I am certainly not in your intellectual league, but I am trying to come along for the ride!

* I wonder what automatic lensometers that labs are using?
* I wonder what auto lensometer that the labs that are pushing *free-form* and *digital* processing are using to check their work.
* I wonder what those labs are using to calibrate those lensometers?
* I wonder if we all should *believe* what those labs send as a readout for verification of lenses from those lensometers?

I wonder too.
I can tell you that my lab uses the calibration kit from the lensometer manufacturer to calibrate the Humphrey. It has lenses in +/- 20 D, 15 D, 10 D, and 5 D, with specs to the nearest hundreth. Also, a 7D prism that you rotate 90 degrees 4X, and a cal instrument for the pd reader as well. Either I or our maint tech calibrate them. No one else has the codes.
Wes

[Wes]

The frame was locked down but there were 2-3 millimeters of play where the window continually read that the lens was aligned. Within this area, there were two slightly different readings for this particular pair of glasses.

Sounds like a wave in the lens to me. Do you still have the pair? Hold it in front of your eye and look at a print pattern, and move the lens around slightly. If there appears to be distortion, it's a wave in the lens. Course, it could also be a dirty/scratched lens.
Wes

[RT]

Do you read in quarter diopters or eighths? I had the machine set to quarter stops which led to the rounding discrepancies. Otherwise, the machine did a great job and did it fast.

What??? Quarter diopter rounding??? You mean TWICE the ANSI tolerance on most powers??? I rarely agree with the old hairy-chested opticians on this board, but really, you need to tighten down your tolerances if you want to be taken seriously. You should probably be verifying at 1/16th diopter, similar to what your lab is probably doing.

I wonder what auto lensometer that the labs that are pushing *free-form* and *digital* processing are using to check their work.

The labs that I am familiar with use specialized equipment for checking FreeForm designs. They are not using an "off-the-shelf" auto-lensometer. Given the aperture size of a typical auto-lensometer, they could only check a limited area, and not evaluate whether or not the lens matches the intended design.

If checking *free-form* or *digitally processed* lenses, do we accept what you are questioning.................or a much higher accuracy?

I'm not sure how you believe the method of surfacing a lens and the tolerance for design accuracy are related. You are raising two separate questions...one is whether or not the power reading in the lensometer matches the requested power. The other is whether or overall lens matches the intended design. You are right in asking if a there is a possibility that a lens could measure as "on-power" but be fundamentally different than the design.

But...that could happen with a conventional front-molded progressive too. How do you verify that a conventional progressive matches the intended design??? You don't--you just verify that the power matches in the distance verification circle, and many opticians don't even verify the power in the near. The fact of the matter is that you have always assumed that the lens provided the intended design, as long as the power measured in the distance circle matched the requested power.

It's not bad that you want to verify that the FreeForm (digitally surfaced) lens completely delivers the intended design in all areas of the lens, but you've never ever checked that on lower tech designs in the past. I'm not sure why you suddenly need an order-of-magnitude-improvement in lens verfication. It would be nice if every ECP had a calibrated gonculator that verified whether or not each progressive lens matched the theoretical design behind that lens. In practice, however, the price per office would be absolutely prohibitive, and it is doubtful that a significant number of dispensed lenses would be flagged as bad.

[icare]

Automated lensometers are designed to allow people educated during the "dumbing down of America" to be employed in the optical office. They serve their pupose. They also furnish computer print outs that impress those who question the accuracy of the person using a manual lensometer, they serve their purpose. Ralph Drew once said: "There's nothing that impresses a doctor more than an computer print out from a lensometer."
Manual lensometers were designed to be used by Opticians. They do this well.

Chip

+1 Chip. I concur.

[icare]

In all but three pair, the automatic lensometer got the same reading as the ordinary lensometer. Two of the three were just rounded differently but the last one was a complete mystery. It claimed there was a 0.25 cyl in a lens that was actually a sphere. When I aligned the glasses slightly different (but still centered), the cyl reading disappeared.

So tell me, what opinion do you have on automatic lensometers? Do you use them in your office? Do you hide them under the doc's sink? I'm curious.

I think it's interesting how many people have told me that they determine the accuracy of an automated lensometer by comparing it against a manual lensometer. It seems that the manual method has yet to be unseated as the 'go-to' standard when you really want to know what the patient is wearing.

I've seen way too many ineffective automated lensometers to start shopping for one now. I'm also in the market for an additional manual model for an exam room.

[MarcE]

I think it's interesting how many people have told me that they determine the accuracy of an automated lensometer by comparing it against a manual lensometer. It seems that the manual method has yet to be unseated as the 'go-to' standard when you really want to know what the patient is wearing.

I've seen way too many ineffective automated lensometers to start shopping for one now. I'm also in the market for an additional manual model for an exam room.

I have to disagree; and I'm with Barry S. I think that the Humphrey is better than many of the others out there.

I used to feel like you. Now I believe that I could calibrate my manual with my auto - but not the other way around.

Of the three labs that I have visited in the last couple of years, this is what they use for verification:
B&L 70, Humphrey 350, Humphrey 360.

And to Chip - actually a printout is worth something. At least is proves that the lens was actually checked. And it proves that they checker didn't "fudge" the numbers. They may have twisted, tilted, bent, or licked the lens to get it to read correctly - but at least they checked.

With a manual, I have only your word.

And maybe my eyes are bad, but it's hard for me to get to 1/16ths precision on a manual (not impossible, but difficult).

[Wes]

I can feel a lens in a manual lensometer, with an autolensometer, its more like a clinical transaction...
Wes

[MarcE]

Do you ever notice how the original song is always better than the remake? It seems always to be true.

It was even true for this young lady I met that heard a "remake" of the song Signs by Tesla. (she unwittingly was listening to my "classic rock" radio station) Apparently this new band, Five Man Electric Band, remade one of her favorite songs. She didn't like the "New" version as well.:hammer:

Just use the autolensometer. Like Tesla, it's an aquired taste.

[Chris Ryser]

Automated lensometers are designed to allow people educated during the "dumbing down of America" to be employed in the optical office.

Manual lensometers were designed to be used by Opticians. They do this well.
Chip

So funny...................................and well said

[cocoisland58]

Automated lensometers are designed to allow people educated during the "dumbing down of America" to be employed in the optical office. They serve their pupose. They also furnish computer print outs that impress those who question the accuracy of the person using a manual lensometer, they serve their purpose. Ralph Drew once said: "There's nothing that impresses a doctor more than an computer print out from a lensometer."
Manual lensometers were designed to be used by Opticians. They do this well.Chip

I can't agree more. I once worked in a lab where the print out was madatory and by manipulating the lens the lab guys could get it to read pretty much whatever they needed it to. I am exaggerating a bit but still. I teach manual lensometry to all my dispensors. You can use automatics but if you don't understand manual it's like using a calculator without actually knowing the math. Now if I can only get the boss to grease the wheel on the ancient B&L my old arthritic hands would be grateful.

[944mo]

The combination of both is the best dont keep it under the sink.
That enviroment is not good for it either.

Try finding the OC on an auto where there is low or no power in one meridian. Better yet put that lens in a auto lensometer/blocker combo and see where it puts the block sometimes.

Yet can you check out a few hundred jobs in eight hours without going insane?.....Wait we are in the optical field that means we already are!
Or be able to get readings in the 100th's.

Why let the auto round for you then you are at its mercy?

I think the only way to have a deserted island with power is if you have Gilligan along to pedal your bamboo bike.:idea:

[hipoptical]

It's too bad we live in an "either/or" society. In this case, both systems of measurement have a place. They are equally useful, and I my opinion, you should use each to verify the other. You still end up making the decision, do you not?
With a manual "meter" the call is more subjective. The auto is purely objective. Objectivity is not ALWAYS the best thing. Sometimes you need more details.
In saying all that- the proper way to inspect digital lenses is with a mapper. Ideally, we would all have and use a mapper to verify lenses (and I would still keep my manual lensometer on standby).
Having said that- I agree with RT.

[Happylady]

I have never used an automatic lensometer. I had never even seen one in use until earlier this year.

I wonder how many new "opticians" have NO idea how to use a standard lensometer or how to measure PDs with a ruler?