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Thread: Double vision in distance on new PAL - troubleshoot help needed

  1. #1
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    Double vision in distance on new PAL - troubleshoot help needed

    Hi there,
    Just looking for a bit of advice before remaking lenses.

    We have an Old PX that is experiencing double vision (horizontal) after a few min of wear when looking at the TV or distance.
    She has tried for 2 weeks already.
    We have dotted up and double checked the RX , PD and fitting heights.
    Background info:
    She is 59 years old
    New Lenses: Zeiss Smartlife Progressive Plus 1.67 into shell frame (came back as standard corridor, although we ordered medium - optom said to let her try first) Measured and triple checked again with Digital measuring device (Visufit)
    Latest RX (verified in room as better by PX by prescribing Optom)
    R: -9.00
    L: -10.00
    Add: +2.00
    Uneven heights: R: 22.5 : 24
    Mono Pd's: R:31 L: 27

    Her old ones don't give her double vision and she never experienced before with any PAL's
    Old lenses from 2015: OSA/Kodak Unique 1.67 into a shell frame
    R: -9.00/-1.25 x 180
    L: -10.50
    Add: +2.50
    Even Heights: 17
    PD: R: 29 L:29

    All her previous PALS's from the past had the same PD and even fitting heights.

    Her double vision is confirmed as "side by side" horizontal in nature.

    At first i thought maybe Zeiss sending the wrong "longer corridor" might be affecting the vision a bit.
    But she only complained of the double vision when doing distance based things like TV or looking far. Always happens after 3-6 min or so.

    The prescribing Optom is suggesting to remake 1. Shorter corridor 2. even up the PD and heights to mimic how she had lenses in the past

    is that a good idea?

    Just a bit stumped by this one as with newer technology lenses like these, usually it is better to be more spot on accurate not like the old conventional PALS which you could play around with a bit.

    Sorry for the essay.. Any help would much appreciated.

    Thank you.

  2. #2
    What's up? drk's Avatar
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    Sounds like a prism problem in the distance portion.

    Let's assume you measured everything just right.

    Let's see what the change in p.d. did.

    Her old glasses had the optical centers:

    2 mm more in, in the right eye, generating unwanted BO
    2 mm more out, in the left eye, generating unwanted BI

    generating this unintentional prism magnitude:

    OD 9D x 0.2cm = 1.8^
    OS 10D x 0.2cm = 2.0^

    so she had been wearing:
    OD ~2 BO
    OS ~2 BI

    So, what was the effect? A yoke-prism, base right.

    Going from having everything shifted to the left to not shifted at all should lead to adaptation problems, but not diplopia. So that's not the answer. Maybe someone can check my work?

  3. #3
    What's up? drk's Avatar
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    What about uncorrected astigmatism? I noticed she had about a diopter of WTR that was not included in the new prescription. Could that cause a monocular diplopia, if she really had astigmatism?

    Again, no, because WTR astigmatism has a vertical diplopia, not horizontal. So we can rule that out.

    (What's more, the astigmatism power change in happening in the vertical meridian, not the horizontal, so the power change hasn't induced any prism change from old glasses to new.)

  4. #4
    What's up? drk's Avatar
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    The only thing that makes any sense, and it's highly unlikely, is that she has a R lateral rectus palsy that doesn't allow her to straighten the R eye (i.e. has an esodeviation), making it go double in straight-ahead gaze, and the old glasses by absolute luck forced her to look away from the deviation, towards a direction of gaze where she can fuse. Chances: about the chance that Kwill212 will get laid tonight.

    This should be easy to confirm: cover test in primary gaze, or at least have her wear the new glasses and turn her head left and right to see if she has double vision with head turned left, and none with head turned right.

  5. #5
    Compulsive Truthteller OptiBoard Gold Supporter Uncle Fester's Avatar
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    This is an example of perhaps fixing what isn't broken with a design change and more exact measurements.

    Yes- you read that right- More exact!

    I get called on the carpet for redo's and this is why I am reluctant to change a design. One less variable when this type of problem pops up.

    Anyone have knowledge of the difference in designs between these two designs that I do not deal with?

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    Master OptiBoarder OptiBoard Silver Supporter
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    Might be underminused. I remember a high myope client who had the same symptoms- they were misinterpreting blur as double vision.

    Hope this helps,

    Robert Martellaro
    Roberts Optical Ltd.
    Wauwatosa Wi.
    www.roberts-optical.com
    ~~~~~~~~~~~~~~~~~~
    Science is a way of trying not to fool yourself. - Richard P. Feynman

    Experience is the hardest teacher. She gives the test before the lesson.



  7. #7
    What's up? drk's Avatar
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    The reality is that, if you didn't botch the readings, and she is telling the truth, then she has an underlying intermittent tropia. Period. Glasses don't "make you go double" without prism. Your eyes make you go double.

    But she may be a poor historian. I'd put her in the phoroptor with pinholes and do a lateral and vertical phoria test to see if there's a muscle problem in primary gaze. If that's normal, then we have to look for ideosyncratic stuff. Have her put on the new glasses and try to elicit it and play around...

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    Compulsive Truthteller OptiBoard Gold Supporter Uncle Fester's Avatar
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    "The reality is that, if you didn't botch the readings, and she is telling the truth, then she has an underlying intermittent tropia. Period. Glasses don't "make you go double" without prism. Your eyes make you go double."

    Why isn't it double in the old pair? That's what will be hard to convince someone without our background to understand.

    Did the measurements mask something? Or is that what you are saying in post #2?

    If so I get it but remain an electric curmudgeon optician.

  9. #9
    What's up? drk's Avatar
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    Yeah, it's a mystery, but what could it be other than prism, if it's truly horizontal binocular diplopia? Chromatic aberration described as horizontal diplopia?

  10. #10
    Compulsive Truthteller OptiBoard Gold Supporter Uncle Fester's Avatar
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    Quote Originally Posted by drk View Post
    Yeah, it's a mystery, but what could it be other than prism, if it's truly horizontal binocular diplopia? Chromatic aberration described as horizontal diplopia?
    Habituated to whatever was wrong in the old pair.

    I try not to overthink this and limit how deep a hole I'm digging before I stop digging. Unless the skies the limit on no charge lab redo's!

    fwiw- I would have explained the rabbit hole this rx and lenses presented before I'd make as many changes as the OP has in this severe myope with a substantial cyl now thrown in.

    Managing expectation is a good thing way more often than not. Under promise and over deliver. And chances are most would come back saying the Zeiss lenses are better. But going down this hole allowing a onetime n/c redo limits the pain (and time spent!) before I hit bottom.
    Last edited by Uncle Fester; 10-17-2022 at 04:08 PM. Reason: tweak...

  11. #11
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    Thanks, Drk...

    But I have had a similar situation. Engineery type patient. Previous Rx.

    -8.75 -1.50 x 160
    -9.50 -.50 x 165
    +2.75

    Made this new Rx using his old frame

    -8.50 -1.50 x 160
    -9.50 -.50 x 165
    +2.75

    Literally everything else the same. A quarter less minus OD is the only change. Complains of double vision. I have the patient come in, glasses check out correct. Continued troubleshooting and trial framing and lens dips. Patient claims horizontal shadowing kind of ghosted double vision. Stick a quarter minus trial lens in front of the glasses and it disappears. Why? Not a clue. But I remade the lenses with the -8.75 OD and he's happy as a clam.

    I would grab a -1.25 cyl trial lens, hold it in front of their new glasses right eye x 180 and see if the problem resolves or is better at least.

  12. #12
    What's up? drk's Avatar
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    Well that is indeed the lowest-hanging fruit. Depends on what kind of followup they did. I would hope that was looked at!

    (But why only after some time worn, etc.? Who knows? People are all unique...)

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    Master OptiBoarder CCGREEN's Avatar
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    Tell us about lens material please.
    High powers like this lens material makes a lot of difference. From the description I am hearing I am suspecting some chromatic aberration going on. "shadowing kind of ghosted double vision."
    Double vision? in what direction are the images?

  14. #14
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    Quote Originally Posted by CCGREEN View Post
    "shadowing kind of ghosted double vision."
    Double vision? in what direction are the images?

    That's what I wrote about a previous patient of mine, not the subject of this post.

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    Master OptiBoarder optical24/7's Avatar
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    I’ve always found it fascinating how the eye/brain connection adapts……or doesn’t. I’ve found serendipitously, that approximately 2-3 years of visual habituated use of eyes can significantly effect outcomes in adaption to “changes”.

  16. #16
    Compulsive Truthteller OptiBoard Gold Supporter Uncle Fester's Avatar
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    I agree with 24/7 100%.

    If they are VSP I almost always switch them, when in another lens design, to the Via Elite 2 with TechShield Elite UVR and close to 100% success. The few failures I've had are remedied by the one time no additional charge redo.
    Last edited by Uncle Fester; 10-19-2022 at 11:09 AM. Reason: tweak...

  17. #17
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    Thanks for all the replies, we will take them into consideration for solution.

    Just a note: We are not doing new lenses into old frame, she made a new separate pair. But both the new and old frames are acetate and similar size

    Someone asked about the lens material: they are both 1.67 high index.

    Cheers.

  18. #18
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    It's obvious the problem is uneven seg hts! Even out the segs to 23 or 23.5 and all will be well.... in my humble opinion.

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    Quote Originally Posted by onthegrind View Post
    It's obvious the problem is uneven seg hts! Even out the segs to 23 or 23.5 and all will be well.... in my humble opinion.
    Have you measured the patient? How is it obvious that uneven seg heights are causing HOIZONTAL double vision?

  20. #20
    Rising Star Cat-Eyes's Avatar
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    assuming you adjusted them prior to measuring and dotted the lens to double check on the patient...my guess is the cyl difference is causing blur which they interpret as double vision. Im curious to know if you found the solution?
    "One should either be a work of art or wear a work of art" - Oscar Wilde

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