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Thread: Need help with aneisotropia due to scleral buckle

  1. #1
    Master OptiBoarder OptiBoard Silver Supporter rdcoach5's Avatar
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    Need help with aneisotropia due to scleral buckle

    My pt sees things closer with right eye than left eye not due to Rx but to buckle which has caused his rt cornea to thicken and is therefore not in the same plain as the left.I used Opticampus calculator to see how much changing the base curve and/or thickness will change magnification.

    O.D -0.75+2.00x170 Add2.75 Spect mag -0.3%/2.5 % with 2.6 ctr/4.5 bc
    O.S. -0.25+1.50x005 +.4%/2.5% 2.6 ctr/4.5 bc 5 bc/2.6 ct .5%/2.6% 3.0 ctr 5.5 BC .7%/2.8%

    Any opinions on correct trial? I'm assuming option 3, 3.0 ct/5.5 bc would be worth a trial as it is not too much diff than what the pt is used to. any help would be appreciated. I cannot be more specific on the amount of aneisotropia, only that he notices it and is pretty well adjusted to it the way it is. Thanks

  2. #2
    One eye sees, the other feels OptiBoard Silver Supporter
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    How long has it been since the surgery? Aniseikonia testing may or not be be required depending on the symptoms. I would check with the surgeon and prescribers before proceeding, although you might try a size lens to gauge the client's reaction, helping you decide how hard to push for further testing. If you don't have size lenses, and do have trial lenses with biconvex plus, piggyback a -20 and +20 for about 5% magnification or minification, depending on the orientation.

    https://www.reviewofoptometry.com/ar...with-the-class
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    Master OptiBoarder OptiBoard Silver Supporter rdcoach5's Avatar
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    Thanks for the response and that link, Robert. He has had the Macular Pucker , not buckle, for 2 years. I mis- remembered the diagnosis. Please explain the use of piggybacked + and - 20 lenses to ck mag difference.
    Thanks, Bob

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    What's up? drk's Avatar
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    Are you assuming he has different cortical image sizes because of a macular peel surgery? If so, I'd look for that online to see if it's been reported. I don't know of that occurring.

    Scleral buckling, yeah. (Cornea is not involved in that, BTW.)

    If he just says something "seems closer", that's a pretty broad symptom, you know?

  5. #5
    One eye sees, the other feels OptiBoard Silver Supporter
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    Quote Originally Posted by rdcoach5 View Post
    Thanks for the response and that link, Robert. He has had the Macular Pucker , not buckle, for 2 years. I mis- remembered the diagnosis. Please explain the use of piggybacked + and - 20 lenses to ck mag difference.
    Thanks, Bob
    Your welcome, Bob.

    The -20 DS trial lens (see below) is bi-concave, -10 on each side. The +20 DS lens is bi-convex, +10 on each side. Together, they fit better than OJ's glove. The center thickness when joined is 8mm. With the minus side away from the eye (for a -10 BC), the spectacle magnification is -5.1%, and when the plus side is away from the eye (+10 bc), 5.5%.

    Lowering the power (ct 5.5mm and ±5 BCs) yields -1.8% and 1.8% respectively, according to http://www.opticampus.com/tools/magnification.php
    Attached Thumbnails Attached Thumbnails ±20b.jpg   ±20a.jpg  
    Science is a way of trying not to fool yourself. - Richard P. Feynman

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    I agree with Robert that a quick and easy way to "test" the amount of magnification needed is to use trial lenses. When piggy backing the lenses, putting the minus closer to the patient should magnify and switching should minify (did I spell that right? Looks weird. Haha). It seems like it'll be a tough task if you don't have an idea of the amount of aniseikonia present, though maybe it's not something that the patient is so sensitive to considering he is "well-adjusted" to his current situation. In any case, 5% mag seems to be a bit too much to compensate. I'd suggest starting with lower powers - if the mag difference is 5% or more, there may not be a good chance of fusion anyway.

    Edit: I see that Robert already address the lower mag... a little late to the party... :-/
    Last edited by musicvirtuoso; 06-01-2016 at 04:36 PM.

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    Hmm... interesting. I can understand how a macular pucker could affect image size, but wouldn't macular peel surgery help that?

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    Master OptiBoarder OptiBoard Silver Supporter rdcoach5's Avatar
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    Quote Originally Posted by musicvirtuoso View Post
    Hmm... interesting. I can understand how a macular pucker could affect image size, but wouldn't macular peel surgery help that?
    Don't know but it sounds risky

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    Master OptiBoarder OptiBoard Silver Supporter rdcoach5's Avatar
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    reporting back after pt picked up new lenses. He said it helped a lot ! I went with 1/2 diop steeper base curve and .4 thicker to increase magnification on his
    left lens.

  10. #10
    What's up? drk's Avatar
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    Half diopter steeper?
    1/2 mm thicker?

    That's really not much.

  11. #11
    Master OptiBoarder OptiBoard Silver Supporter rdcoach5's Avatar
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    No , but it helped. Something to keep in mind. According to Opticampus , .2% but he was pretty used to his glasses before. I didn't want to rock the boat.

  12. #12
    One eye sees, the other feels OptiBoard Silver Supporter
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    Quote Originally Posted by rdcoach5 View Post
    reporting back after pt picked up new lenses. He said it helped a lot ! I went with 1/2 diop steeper base curve and .4 thicker to increase magnification on his
    left lens.
    Thanks for the follow-up. Do you mean the right lens?

    The image size disparity decreases about .2% at 180, but increases about .2% at 90. The only way to keep that from happening is to use a bitoric grind. But at these levels it would be crazy to put the client through the extra expense and the inconvenience of multiple pairs.

    Quote Originally Posted by drk View Post
    Half diopter steeper?
    1/2 mm thicker?

    That's really not much.
    Placebo effect?
    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.



  13. #13
    Master OptiBoarder OptiBoard Silver Supporter rdcoach5's Avatar
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    Left lens. He saw a closer image in his right eye before new lenses. I did not tell him that I was increasing base curve and thickness. It's not much but he's more comfortable.
    Last edited by rdcoach5; 06-11-2016 at 06:50 AM. Reason: add

  14. #14
    One eye sees, the other feels OptiBoard Silver Supporter
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    Sorry Bob, I missed the description of your client's symptoms in your first post, so yes, we want to increase the magnification of the left lens, although as drk said, objects looking closer in one eye is a somewhat vague symptom.

    To be sure, those with normal binocular vision can easily discern differences of .25% to .50% in image size, most are asymptomatic until differences are above 1%, possibly lower when there is astigmatism.

    http://www.medrounds.org/optics-review/2006/05/29.html

    Aniseikonia is possible with a variety retinal disorders, including epiretinal membranes.

    http://iovs.arvojournals.org/article...icleid=2407559

    Because of the aging population, we're seeing more problems with aniseikonia. Nice going recognizing your client's visual discomfort and finding a solution that appears to have given them some relief.

    Best regards,
    Last edited by Robert Martellaro; 06-11-2016 at 01:56 PM.
    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.



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