Results 1 to 12 of 12

Thread: Prismus Maximus

  1. #1
    What's up? drk's Avatar
    Join Date
    Mar 2004
    Location
    Ohio
    Occupation
    Optometrist
    Posts
    8,645

    Prismus Maximus

    OK, my patient/aunt has some kind of progressive orbitopathy (that I have to farm out to someone who knows his/her/xe's stuff) with a wicked newer esotropia and vertical tropia. She's successfully been in prism along the way in her journey (about 6^ BO OD and OS--no vertical) but it's getting worse.

    I need to deliver about 7 BO OD and OS, and now about 7 BU OD and 7 BD OS, in order to achieve binocular fusion.

    Is this do-able? Any tips?

    (Want a new outside Rx?)
    (Want a new aunty?)

  2. #2
    Eyes eastward... Uilleann's Avatar
    Join Date
    Jan 2007
    Location
    Utah
    Occupation
    Dispensing Optician
    Posts
    3,066
    Should be do-able, but I certainly wouldn't want to be the one to surface it! Not sure if digital cutting allows that range or not, but of course small and ROUND would be the order of the day. The ability to rotate the lens in frame a few degrees will make the final fit that much more flexible. But I'm only preaching what yinz already know...

  3. #3
    Master OptiBoarder
    Join Date
    Feb 2016
    Location
    usa
    Occupation
    Dispensing Optician
    Posts
    779
    It's possible. It might need to go to a specialty lab like EPIC though.

    I recently filled a

    -10.25 -3.00 x 165 10 BO 3.5BU
    -8.25 -3.25 x 021 10 BO 3.5BD

    with the best part of course being a 52 pd, adjusted for prism meant a distance PD of 46!

    What's aunties VA's?

  4. #4
    Master OptiBoarder OptiBoard Silver Supporter
    Join Date
    Jul 2002
    Location
    Wauwatosa Wi
    Occupation
    Dispensing Optician
    Posts
    5,264
    Quote Originally Posted by drk View Post
    Any tips?
    It's time to loose the PALs- Rx separates or segmented (segs will be significantly different in heights).

    Avoid low Abbe materials.

    Avoid free-form even if the fabricators say it's doable.

    Show prism samples to demo their inherent poor cosmesis at this level of prism.

    Discuss press-on prisms.

    Make sure bottom of OS lens clears the cheek, and the brow on the OD- use a heavy safety bevel or light roll.

    Trial frame to gauge adaptability- wait until at home before wearing.

    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.



  5. #5
    What's up? drk's Avatar
    Join Date
    Mar 2004
    Location
    Ohio
    Occupation
    Optometrist
    Posts
    8,645
    So...

    1. frame selection
    2. no low abbe materials
    3. avoid PAL
    4. traditional surfacing

    Thank you.


    P.S. normal VAs

  6. #6
    Master OptiBoarder
    Join Date
    Feb 2016
    Location
    usa
    Occupation
    Dispensing Optician
    Posts
    779
    You will need to adjust the PD 2mm narrower for each eye, and the fitting heights 2mm down on the right and 2mm up on the left. If there is significant power to go along with the prism you may also need to adjust the prism amount, add prism for plus power, lower prism power for minus power.

  7. #7
    Master OptiBoarder
    Join Date
    Feb 2013
    Location
    PA
    Occupation
    Dispensing Optician
    Posts
    1,572
    So this pt went from zero vertical to a total of 14? Wow... there will be some adaptation. Definitely wouldn't recommend progressives.

  8. #8
    Compulsive Truthteller OptiBoard Gold Supporter Uncle Fester's Avatar
    Join Date
    Dec 2004
    Location
    At a position without dimension...
    Occupation
    Dispensing Optician
    Posts
    5,018
    Quote Originally Posted by drk View Post
    OK, my patient/aunt has some kind of progressive orbitopathy (that I have to farm out to someone who knows his/her/xe's stuff) with a wicked newer esotropia and vertical tropia. She's successfully been in prism along the way in her journey (about 6^ BO OD and OS--no vertical) but it's getting worse.

    I need to deliver about 7 BO OD and OS, and now about 7 BU OD and 7 BD OS, in order to achieve binocular fusion.

    Is this do-able? Any tips?

    (Want a new outside Rx?)
    (Want a new aunty?)
    Ryser's Rule?

    First fresnel the vertical see if she can adopt with her current progressive?

  9. #9
    Master OptiBoarder
    Join Date
    Feb 2013
    Location
    PA
    Occupation
    Dispensing Optician
    Posts
    1,572
    Quote Originally Posted by Uncle Fester View Post
    Ryser's Rule?

    First fresnel the vertical see if she can adopt with her current progressive?
    I did that the other day with some older patient. It was 5 diopters. He said he couldn't tell much difference. I prayed when I saw him walking out of the building. He looked like he was drunk.

  10. #10
    What's up? drk's Avatar
    Join Date
    Mar 2004
    Location
    Ohio
    Occupation
    Optometrist
    Posts
    8,645
    Hey! Fester for the win. Brilliant suggestion. May take her out of the patch for the meanwhile, too.

  11. #11
    Master OptiBoarder
    Join Date
    Feb 2013
    Location
    PA
    Occupation
    Dispensing Optician
    Posts
    1,572
    Coincidently the guy I put the fresnel on just came in .... he's adapting quite well to the prism. Diplopia is gone but has a little depth perception issues. It hasn't been that long so he has been advised to wear a bit longer. He also has an appointment scheduled to see OMD regarding surgery.

  12. #12
    What's up? drk's Avatar
    Join Date
    Mar 2004
    Location
    Ohio
    Occupation
    Optometrist
    Posts
    8,645
    Anyone with fusion so bad they need Fresnel prism cannot expect much in the way of stereoacuity, if even because of the blur (but it's really from the bare alignment).
    The best to expect is no diplopia.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. Practice Maximus Starter disk?
    By cb8774 in forum Computer and Software Help
    Replies: 0
    Last Post: 08-04-2020, 10:52 AM

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
  •