Page 1 of 2 12 LastLast
Results 1 to 25 of 29

Thread: Mono PD VS Binocular Situation...........

  1. #1
    Bad address email on file
    Join Date
    Aug 2010
    Location
    Canada
    Occupation
    Optical Retail
    Posts
    95

    Mono PD VS Binocular Situation...........

    If the mono pd measurements you took came out to be 32.5/34.5

    Current glasses px has been wearing are binocular at 33.5/33.5

    Would you match the old pd or correct it to the proper measurement????

  2. #2
    ABOM Wes's Avatar
    Join Date
    Nov 2007
    Location
    Earth
    Occupation
    Optical Laboratory Technician
    Posts
    3,194
    Is it a lined bifocal, progressive, other type of multi? High rx or low? What is the RX anyway? How can we advise you with no info? Most of the time, I would ue the PD's as measured and discuss expectations with pt.
    Wesley S. Scott, MBA, MIS, ABOM, NCLE-AC, LDO - SC & GA

    “As our circle of knowledge expands, so does the circumference of darkness surrounding it.” -Albert Einstein

  3. #3
    Master OptiBoarder OptiBoard Silver Supporter rdcoach5's Avatar
    Join Date
    Dec 2006
    Location
    Rossford, Ohio
    Occupation
    Dispensing Optician
    Posts
    1,604
    depends on how you arrived at your mono PD. If you spotted it with a felt tip, measured it AND verified it with new frame on and verified that the old was off by spotting with a felt tip using the engraved fitting marks and verifying that the pd was off using a penlight, go with the new mono PD. If all you used was a pupilometer, the current glasses are as likely to have the correct PD as your new measurement.

  4. #4
    Master OptiBoarder OptiBoard Silver Supporter Barry Santini's Avatar
    Join Date
    May 2000
    Location
    Seaford, NY USA
    Occupation
    Dispensing Optician
    Posts
    6,008
    Quote Originally Posted by Mrmessi View Post
    If the mono pd measurements you took came out to be 32.5/34.5

    Current glasses px has been wearing are binocular at 33.5/33.5

    Would you match the old pd or correct it to the proper measurement????
    I don't know. But I ask:

    How do you *know* that *your* measurements are the ones that are "correct"?


    B

  5. #5
    Bad address email on file
    Join Date
    Aug 2010
    Location
    Canada
    Occupation
    Optical Retail
    Posts
    95
    Quote Originally Posted by wss2020 View Post
    Is it a lined bifocal, progressive, other type of multi? High rx or low? What is the RX anyway? How can we advise you with no info? Most of the time, I would ue the PD's as measured and discuss expectations with pt.
    Progressive lens, it was a general question, i used it as an example.

    What if the patient has adapted to the wrong measurements and when you correct it they find it difficult to adjust???? Does this ever happen????

    Does it make a difference if the power is in plus or minus?????

  6. #6
    ABOM Wes's Avatar
    Join Date
    Nov 2007
    Location
    Earth
    Occupation
    Optical Laboratory Technician
    Posts
    3,194
    If they can adapt to crap measurements, they can readapt to the proper ones. Ask em if they've had trouble with their reading and intermediate. Ask em if they felt like they've had to turn their head slightly and look out of the glasses at a bit of an angle. Tell em what you're doing and why and they'll love you for it.

    *assuming your measurements are correct!
    Wesley S. Scott, MBA, MIS, ABOM, NCLE-AC, LDO - SC & GA

    “As our circle of knowledge expands, so does the circumference of darkness surrounding it.” -Albert Einstein

  7. #7
    OptiBoardaholic eyeguy21's Avatar
    Join Date
    Aug 2010
    Location
    Missouri
    Occupation
    Dispensing Optician
    Posts
    240
    My question would be, "aren't those pd's within tolerance of each other anyways? If you went with your measurements and they came back from the lab with the previous measurements you listed you'd most likely be just fine. I generally go with my own measurements and if the measurements I came up with cause me to make any kind of significant change I'll discuss it with them so they know what to expect upon delivery. But especially if you're talking about PAL's I'll generally use my own measurements.
    "Wise men don't need advice. Fools won't take it." - Benjamin Franklin.

  8. #8
    ABOM Wes's Avatar
    Join Date
    Nov 2007
    Location
    Earth
    Occupation
    Optical Laboratory Technician
    Posts
    3,194
    Quote Originally Posted by eyeguy21 View Post
    My question would be, "aren't those pd's within tolerance of each other anyways? If you went with your measurements and they came back from the lab with the previous measurements you listed you'd most likely be just fine. .
    This logic is completely faulty. I don't spot up or layout lenses "within tolerances"; why would I order them that way? The more exact you are at each end every step of the process, the more likely you'll have an acceptable end product. Just imagine lab techs saying, oh, let me just get within 14 degrees of axis for this .25 cyl when I spot it up, thats within tolerance.

    The precision that you use for what you order directly affects what you receive as an end product, and "acceptable standards" should only apply to the end product.

    Be precise. Your patients deserve it.
    Wesley S. Scott, MBA, MIS, ABOM, NCLE-AC, LDO - SC & GA

    “As our circle of knowledge expands, so does the circumference of darkness surrounding it.” -Albert Einstein

  9. #9
    OptiBoardaholic eyeguy21's Avatar
    Join Date
    Aug 2010
    Location
    Missouri
    Occupation
    Dispensing Optician
    Posts
    240
    Quote Originally Posted by wss2020 View Post
    This logic is completely faulty. I don't spot up or layout lenses "within tolerances"; why would I order them that way? The more exact you are at each end every step of the process, the more likely you'll have an acceptable end product. Just imagine lab techs saying, oh, let me just get within 14 degrees of axis for this .25 cyl when I spot it up, thats within tolerance.

    The precision that you use for what you order directly affects what you receive as an end product, and "acceptable standards" should only apply to the end product.

    Be precise. Your patients deserve it.
    I try not to disagree with you Wes, I learned my lesson (kidding). I don't think we're on different pages on this one though. I'm not saying don't be accurate. In fact far from it. That's why I'm advocating taking your own measurements rather than following the previous pair (which I will use as a guideline mostly). Especially with progressives. On the other hand I almost always specify a mono PD even if it's just a pair of SV lenses. If I ask for 32.5/34.5 and get 33.5/33.5 I'm not going to raise to much of a stink over it.

    Precise? Absolutely. Nit-picky? Uuummmm, maybe. Depends on the situation. Like you mentioned earlier this thread posed a pretty general question without many details. Some of our "cackling" hens (if you remember that) are so nit-picky that it's difficult to get a pair checked in. So much so that it strains our relationship with the lab.

    14 degrees off axis seems like a more serious situation than what was presented here but I understand your point. Completely faulty logic though? That seems a little harsh. It's not like I strive for mediocrity.

    Just out of curiosity, would you reject a pair of pals in the above situation?
    "Wise men don't need advice. Fools won't take it." - Benjamin Franklin.

  10. #10
    ABOM Wes's Avatar
    Join Date
    Nov 2007
    Location
    Earth
    Occupation
    Optical Laboratory Technician
    Posts
    3,194
    Ahh. I rescind my "completely faulty" comment. Still, we're being asked by someone whom I suspect has little experience from other posts, so our answers should leave little room for doubt.

    As far as "would I accept them?". Probably, assuming the PATIENT could accept them. I certainly wouln't order them that way though. I've seen "people who call themselves opticians" order glasses with just such a situation, claiming its within standards. Foolish in the extreme, if you ask me. I thought that's what you were suggesting. Sorry!
    Wesley S. Scott, MBA, MIS, ABOM, NCLE-AC, LDO - SC & GA

    “As our circle of knowledge expands, so does the circumference of darkness surrounding it.” -Albert Einstein

  11. #11
    ABOM Wes's Avatar
    Join Date
    Nov 2007
    Location
    Earth
    Occupation
    Optical Laboratory Technician
    Posts
    3,194
    In fact, I met one old guy who measured all his patients canthus to canthus! When his apprentice became my apprentice, I had a lot of nonsense to purge from his head.
    Wesley S. Scott, MBA, MIS, ABOM, NCLE-AC, LDO - SC & GA

    “As our circle of knowledge expands, so does the circumference of darkness surrounding it.” -Albert Einstein

  12. #12
    OptiBoardaholic eyeguy21's Avatar
    Join Date
    Aug 2010
    Location
    Missouri
    Occupation
    Dispensing Optician
    Posts
    240
    Yeah, I would agree with that completely. My intention is to be as accurate as possible 100% of the time. Falling short of that (slightly only) I rely on the lab standards which are actually more stringent than ANSI. I think they have a tolerance of about 1mm for horizontal imbalance rather than 2 or 2.5 which is what I think ANSI is. From there I just weigh it out based on the circumstance.

    But absolutely you want to start off with accurate measurements so that you can fall back on the tolerances. I mean if your off to begin with and then the finished product is off even further you could be quite a ways off of the correct mark. Your next reply came on my blackberry before I finished this one but I think it kind of feeds into my thought here. And again, I agree.
    "Wise men don't need advice. Fools won't take it." - Benjamin Franklin.

  13. #13
    Master OptiBoarder
    Join Date
    May 2000
    Location
    Fayetteville, NC, USA
    Occupation
    Dispensing Optician
    Posts
    2,009
    Quote Originally Posted by wss2020 View Post
    In fact, I met one old guy who measured all his patients canthus to canthus! When his apprentice became my apprentice, I had a lot of nonsense to purge from his head.

    A prime example of why there should be NO apprentices. These poor folks are dependant on many folks who have absolutely no clue. AND before someone asks "how do we train them then?"..........send them to school so they will effectively learn.

  14. #14
    ABOM Wes's Avatar
    Join Date
    Nov 2007
    Location
    Earth
    Occupation
    Optical Laboratory Technician
    Posts
    3,194
    Quote Originally Posted by wmcdonald View Post
    A prime example of why there should be NO apprentices. These poor folks are dependant on many folks who have absolutely no clue. AND before someone asks "how do we train them then?"..........send them to school so they will effectively learn.
    Amen brother! I haven't been impressed with the quality of opticians I've seen from the apprentice side. To be sure, there are exceptions, but those are rare. Most people will only learn what they're taught; they dont seek knowledge like our optiboarders. Therefore, they can only learn from the guy who taught them, and there aren't a lot of worthy masters/teachers still apprenticing noobs.
    Wesley S. Scott, MBA, MIS, ABOM, NCLE-AC, LDO - SC & GA

    “As our circle of knowledge expands, so does the circumference of darkness surrounding it.” -Albert Einstein

  15. #15
    Master OptiBoarder OptiBoard Silver Supporter Barry Santini's Avatar
    Join Date
    May 2000
    Location
    Seaford, NY USA
    Occupation
    Dispensing Optician
    Posts
    6,008
    Ratcheting-up the need for extreme precision in fabrication, without *fully* understanding the overall client-tolerance and benefit equation (we typically *infer* that tighter tolerance = superior vision) is misplaced cost placement, IMHO.

    I think if we were to review what we currently unknowingly tolerate or are not fully cognizant of in today's delivery of eyewear, we'd get a big eyeful about how and where to allocate increased precision demands.

    I'm all for better. I'm just not sure that the current refractive paradigm, together with our the majority of our present measurement tools (pupilometers, PD rulers, layout/centration protractors, corneal reflex ID cardinals, etc.) merits such appranetly extreme adherence to (my word here) *micro-precision* in measuring and fabrication expectations.

    But I am open for discussion about here about it.

  16. #16
    Master OptiBoarder OptiBoard Silver Supporter Barry Santini's Avatar
    Join Date
    May 2000
    Location
    Seaford, NY USA
    Occupation
    Dispensing Optician
    Posts
    6,008
    For example, tightened PD tolernances without consideration of the combined effects of Base curve, Rx, client posture, Vertex and panto and overall frame fit is misplaced energy, IMHO.

    B

  17. #17
    Master OptiBoarder
    Join Date
    Oct 2004
    Location
    Down in a hole!
    Occupation
    Dispensing Optician
    Posts
    13,078
    Quote Originally Posted by Barry Santini View Post
    For example, tightened PD tolernances without consideration of the combined effects of Base curve, Rx, client posture, Vertex and panto and overall frame fit is misplaced energy, IMHO.

    B
    What is the better approach?

  18. #18
    Master OptiBoarder OptiBoard Silver Supporter Barry Santini's Avatar
    Join Date
    May 2000
    Location
    Seaford, NY USA
    Occupation
    Dispensing Optician
    Posts
    6,008
    We should simultaneously advance in our fitting and verification tools, while developing a more complete understanding of what deviations are reasonable to tolerate for *most* clients.

    Barry

  19. #19
    OptiWizard
    Join Date
    Nov 2009
    Location
    On a Ship of Fools
    Occupation
    Dispensing Optician
    Posts
    346
    Quote Originally Posted by Barry Santini View Post
    We should simultaneously advance in our fitting and verification tools, while developing a more complete understanding of what deviations are reasonable to tolerate for *most* clients.

    Barry
    How?

  20. #20
    Master OptiBoarder OptiBoard Silver Supporter rdcoach5's Avatar
    Join Date
    Dec 2006
    Location
    Rossford, Ohio
    Occupation
    Dispensing Optician
    Posts
    1,604
    [QUOTE=Barry Santini;363213]For example, tightened PD tolernances without consideration of the combined effects of Base curve, Rx, client posture, Vertex and panto and overall frame fit is misplaced energy, IMHO.


    Barry, I agree there should be more understanding of the Rx and the change of the Rx due to all the factors you mention
    but there is a big difference in all those compensation/calculations between an Rx of -9.00 and one of +0.50 . BUT, I have seen little tolerance in progressives being twisted out of line or with the PD not being aligned correctly. In my experience, if you have them aligned right and they are straight and properly panto'd and the pt still has difficulty, it's time to send the pt back to the Dr for fine tuning the Rx. There is also something that is immeasureable here and that is the fact that some people are way pickier than others. We have all seen pt's come in wearing their old specs that are off PD by 5 mm or so.

    Check List:
    #1 Mark lens with felt tip using engraved marks and adjust on pt to proper panto vertex and face form (or wrap)
    #2 use a penlight to make sure optic axis is aligned with your fitting marks
    #3 Make sure your Rx was written correctly and compare to old Rx. Did Dr or tech mis-write minus instead of plus? for ex.
    #4 Does it help near and far if you add +0.50? if so, -send back to the Dr.
    #5 Is there a condition that prevents the pt from raising their head to a normal position?
    #6 What progressive design do you need for pt's task requirements ?

    Barry I can't think of any more

  21. #21
    Master OptiBoarder OptiBoard Silver Supporter Barry Santini's Avatar
    Join Date
    May 2000
    Location
    Seaford, NY USA
    Occupation
    Dispensing Optician
    Posts
    6,008
    I would begin with an analysis of the errors we currently (perhaps unaware?) tolerate for "satisfied" clients, and try to flesh out the "window" of anecdotal client acceptance.

    I'm sure the ANSI Ophthalmic standards committe has done something of the sort, and not just made isolated calculations based on gemetrical optics-theory.

    Also, an examination of our verification procedure as well. For instance, less reliance on manufacturer-supplied progressive ink markings, and more on verification from enravings ONLY.

    Further, I find the current use of "centration charts" for verification of SV and proressive PDs to often be misprinted/mis-scaled. Try the MJ Passport chart and place a ruler over the 40L to 40R indicies. Multiple rulers in my shop reveal their chart is >0.50mm too narrow.

    That's a start. how many of you have checked and verified the rulers you use, as well as your pupilometers?

    It's a beginning.

    B

  22. #22
    OptiBoard Professional shannon's Avatar
    Join Date
    May 2010
    Location
    Montgomery, Alabama, United States
    Occupation
    Dispensing Optician
    Posts
    177
    Quote Originally Posted by Mrmessi View Post
    Progressive lens, it was a general question, i used it as an example.

    What if the patient has adapted to the wrong measurements and when you correct it they find it difficult to adjust???? Does this ever happen????

    Does it make a difference if the power is in plus or minus?????
    Then assuming the new pd is correct I would expect they would find things to be a hair better. You can adapt to the incorrect thing, but that doesn't mean that there isn't room for improvement. These measurements are not that far off....there's a chance that they would never ever notice a differentce. If its that bad, then we do what we hate, we remake it to the incorrect pd.....as a LAST RESORT! But we need our patients coming back! Politely explain at that point that the previous measurement was a little off and that is what is causing the difference...without bad mouthing anyone....they are usually understanding. But I doubt that you would have much difficulty. They will probably thank you to find that....wow...it's better!


    A man went to an eye specialist to get his eyes tested and asked, "Doctor, will I be able to read after wearing glasses?"
    "Yes, of course," said the doctor, "why not!"
    "Oh! How nice it would be," said the patient with joy, "I have been illiterate for so long."


  23. #23
    Master OptiBoarder OptiBoard Silver Supporter Barry Santini's Avatar
    Join Date
    May 2000
    Location
    Seaford, NY USA
    Occupation
    Dispensing Optician
    Posts
    6,008
    Point #2, "use a penlight to make sure optic axis is aligned with your fitting marks" assumes that the corneal vertex is a reliable indicator of the visual axis.

    I'm not so sure we should not investiate the efficacy of this assumption. I personally have found nurmerous cases where a subjectively determined PD departed by 1+mm from a my best pupilometer PD.

    I use the ol' Designs for Vision approach in cases where I have my suspicions in case of adds over +2.50.

    B

  24. #24
    Master OptiBoarder OptiBoard Silver Supporter rdcoach5's Avatar
    Join Date
    Dec 2006
    Location
    Rossford, Ohio
    Occupation
    Dispensing Optician
    Posts
    1,604
    Quote Originally Posted by Barry Santini View Post
    Point #2, "use a penlight to make sure optic axis is aligned with your fitting marks" assumes that the corneal vertex is a reliable indicator of the visual axis.

    I'm not so sure we should not investiate the efficacy of this assumption. I personally have found nurmerous cases where a subjectively determined PD departed by 1+mm from a my best pupilometer PD.

    I use the ol' Designs for Vision approach in cases where I have my suspicions in case of adds over +2.50.

    B
    I would say that a pupilometer can be off and often is.Not total PD but right and left are off when someones bridge is not uniform or their brow is not, making the pupilometer sit askew.

  25. #25
    OptiBoardaholic
    Join Date
    Jun 2006
    Location
    Katy, Texas
    Occupation
    Dispensing Optician
    Posts
    285
    Um, along the same lines of "how do you know that your measurements are correct?" and "isn't that still within tolerance?" I'm going to chime in and say that I would go with my new measurements for a couple reasons. For one, the PD is split so that could be the original optician just taking a bi-pd and running with it just as easily as if the pd had a perfectly symmetrical face. With the general overall lack of quality in the opticianry world here in Texas, I have learned never to trust others. Secondly, the lenses may have been made to tolerance and are only at that pd because they fell within tolerance. The original maker may have found the exact same pd as I had, but the lab eeked them out a mm off. Definitely within the realm of possibilities so I'm going to have to defer to my own measurements.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Verifying mono PDs
    By AutumN in forum General Optics and Eyecare Discussion Forum
    Replies: 12
    Last Post: 08-11-2007, 01:56 PM
  2. has anyone had mono?!?!
    By catchthevision in forum Just Conversation
    Replies: 11
    Last Post: 03-23-2007, 04:40 PM
  3. Should Mono or Binocular PD'd Be taken on Single Vision & Bifocal lenses??
    By eyesonu38 in forum General Optics and Eyecare Discussion Forum
    Replies: 35
    Last Post: 09-18-2005, 11:22 AM
  4. Binocular?
    By Edgley Gonzaga in forum Ophthalmic Optics
    Replies: 6
    Last Post: 07-06-2002, 01:47 AM
  5. Mono Pd's
    By Rich R in forum General Optics and Eyecare Discussion Forum
    Replies: 2
    Last Post: 09-10-2000, 08:13 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •