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Thread: need help. question about correcting with prism

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    Question need help. question about correcting with prism

    Hello. I have question about correcting phoria / trophia. let the picture describe the condition. My question is which one prescription is the best?. Click image for larger version. 

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    the best mean best for patient adaptation, best for cosmetic, or convenience or anything else.
    thank you

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    Ghost in the OptiMachine OptiBoard Silver Supporter Quince's Avatar
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    I'm not the best person to guide you in this, but it would be much easier to help with a written version of the script. There is obviously a lot of prism here and general I gravitate towards splitting between both eyes evenly (both vertical and horizontal) but that is also dependent of the power correction for each eye as well.
    Have I told you today how much I hate poly?

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    One eye sees, the other feels. OptiBoard Gold Supporter
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    Quote Originally Posted by redb View Post
    Hello. I have question about correcting phoria / trophia. let the picture describe the condition. My question is which one prescription is the best?. Click image for larger version. 

Name:	p prisma gambar.jpg 
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ID:	13949
    the best mean best for patient adaptation, best for cosmetic, or convenience or anything else.
    thank you
    I've never seen this represented on grip paper so I might be interpreting this incorrectly.

    Eliminate examples #1 and #2 because the horizontal prism is base out.

    #3, #4, and #5 are the same, but #3 is written so that the prisms are equally split between both eyes, and this will allow for the best cosmetics and the least negative effects from chromatic aberration (unless the BCVA in one eye is considerably poorer in one eye, if so, split unevenly or put all of the prism in the bad eye).

    Best regards,

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

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    Quote Originally Posted by Quince View Post
    I'm not the best person to guide you in this, but it would be much easier to help with a written version of the script. There is obviously a lot of prism here and general I gravitate towards splitting between both eyes evenly (both vertical and horizontal) but that is also dependent of the power correction for each eye as well.
    thank you for your reply, the condition is left eye is normal 20/20 and right eye 20/20 but with oblique UP 4 Diopter and out 6 Diopter. Im just qurious can we use example 1 or 2 or only 3 is the best. thanks

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    Quote Originally Posted by Robert Martellaro View Post
    I've never seen this represented on grip paper so I might be interpreting this incorrectly.

    Eliminate examples #1 and #2 because the horizontal prism is base out.

    #3, #4, and #5 are the same, but #3 is written so that the prisms are equally split between both eyes, and this will allow for the best cosmetics and the least negative effects from chromatic aberration (unless the BCVA in one eye is considerably poorer in one eye, if so, split unevenly or put all of the prism in the bad eye).

    Best regards,

    Robert Martellaro
    Thank you for your reply, yes I'm describing with picture because i confuse how to describe it. Can you explain more why we have to eliminate example 1 & 2?
    Also. can we use progresive lens for example #3 for Presbiopya. thanks

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    One eye sees, the other feels. OptiBoard Gold Supporter
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    Quote Originally Posted by redb View Post
    thank you for your reply, the condition is left eye is normal 20/20 and right eye 20/20 but with oblique UP 4 Diopter and out 6 Diopter. Im just qurious can we use example 1 or 2 or only 3 is the best. thanks
    #1 and #2 are the only examples that are equal to OD 4BU 6BO. Neither one is optimal for cosmetics. Examples #3, #4, and #5 are using 360 notation, and are equal to OD 4BU 6BI.
    Roberts Optical Ltd.
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    One eye sees, the other feels. OptiBoard Gold Supporter
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    Quote Originally Posted by redb View Post
    Thank you for your reply, yes I'm describing with picture because i confuse how to describe it. Can you explain more why we have to eliminate example 1 & 2?
    Because I misinterpreted the grid paper, and that #3 was the only choice that showed prism split.

    Using the newly supplied Rx, the grid paper with rectangular coordinates, and the center as a reference point, and each box equal to one prism diopter, shows the right eye (small red square bottom left) as OD 2BD 3BO and OS 2BU 3BO. This contradicts what you stated is the written Rx above. Either the Rx you indicated above is written incorrectly, or I am still misinterpreting the graphic.

    Also. can we use progresive lens for example #3 for Presbiopya. thanks
    Generally yes, but with caveats.

    Best regards,

    Robert Martellaro
    Last edited by Robert Martellaro; 06-26-2018 at 10:26 AM.
    Roberts Optical Ltd.
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    www.roberts-optical.com
    ~~~~~~~~~~~~~~~~~~
    Science is a way of trying not to fool yourself. - Richard P. Feynman

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    You can be dead on with your measurements but the patient might not be able or willing to wear what you find. The habitual Rx, the patient symptoms, if any, past experience, should all guide your decision.

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    Quote Originally Posted by fjpod View Post
    You can be dead on with your measurements but the patient might not be able or willing to wear what you find. The habitual Rx, the patient symptoms, if any, past experience, should all guide your decision.
    ok thank you for your advice

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    Quote Originally Posted by Robert Martellaro View Post
    Because I misinterpreted the grid paper, and that #3 was the only choice that showed prism split.

    Using the newly supplied Rx, the grid paper with rectangular coordinates, and the center as a reference point, and each box equal to one prism diopter, shows the right eye (small red square bottom left) as OD 2BD 3BO and OS 2BU 3BO. This contradicts what you stated is the written Rx above. Either the Rx you indicated above is written incorrectly, or I am still misinterpreting the graphic.

    Generally yes, but with caveats.

    Best regards,

    Robert Martellaro
    I mean the right eye condition is misalignment. but i understand your explanation and the correct written prescription. thankyou for all your answer

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    more question. how to measure PD for tropia?. which one is correct? #1 or #2. thanksClick image for larger version. 

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    One eye sees, the other feels. OptiBoard Gold Supporter
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    Quote Originally Posted by redb View Post
    more question. how to measure PD for tropia?. which one is correct? #1 or #2. thanksClick image for larger version. 

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    Of the two choices, #1, if the left eye is stuck in the exo position for all angles of gaze. The Rx might say "balance" for the left eye. But if you cover the right eye and the left eye points straight ahead, measure that position and use this value for the left monocular distance PD.

    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

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    Quote Originally Posted by Robert Martellaro View Post
    Of the two choices, #1, if the left eye is stuck in the exo position for all angles of gaze. The Rx might say "balance" for the left eye. But if you cover the right eye and the left eye points straight ahead, measure that position and use this value for the left monocular distance PD.

    Hope this helps,

    Robert Martellaro
    so the measurement is same. using monocular distance. thanks

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    I have experienced. found patient (40 yo) MPD R32 L32. with tropia in left eye cause by high blood pressure. during 2 months left eye covered, then when i open & check, found Missalignment 23 diopter prism base out. for temporary i give R 8 diopter base out L 9 D base out. (headache if put full prism). after 3 months check again the eyes back to normal (both eye) no tropia found.
    The question is, is that coincidence or normal for high blood pressue patient? thank you

  15. #15
    What's up? drk's Avatar
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    Muscle palsys can resolve, so yes.

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