Results 1 to 14 of 14

Thread: prescribed prism with slab-off

  1. #1
    OptiBoard Novice
    Join Date
    Jul 2009
    Location
    rockford il
    Occupation
    Optical Laboratory Technician
    Posts
    2

    Confused prescribed prism with slab-off

    We have a patient whos' doctor has prescribed combined prism in both eyes with a slab-off. Patient is currently wearing a progressive hi index lens.
    Rx: od: +.75-.50x145 4bd 4bo
    os: -4.00-1.50x180 3bu 4 bo
    +2.75 add ou


    Will a slab-off change prism in a progressive(in lft eye)????

  2. #2
    Master OptiBoarder
    Join Date
    May 2000
    Location
    Fayetteville, NC, USA
    Occupation
    Dispensing Optician
    Posts
    1,504
    No.....it will not affect the bi-centric grind in any way.

  3. #3
    OptiBoard Novice
    Join Date
    Jul 2009
    Location
    rockford il
    Occupation
    Optical Laboratory Technician
    Posts
    2
    Patient has struggled with double vision for years. She went to University of Wisconsin where the Doctors were very specific in prescribing her prism. With a slab-off being base down prism, and the doctors asking for prism Up in that eye, will we be safe using the slab-off? The patient has tried a line but refuses to have a line showing, eventhough it is the best way to go .

  4. #4
    ATO Member OptiBoard Bronze Supporter HarryChiling's Avatar
    Join Date
    Apr 2005
    Location
    Nowhereville
    Occupation
    Other Eyecare-Related Field
    Posts
    7,503
    Blog Entries
    1
    Quote Originally Posted by mwh1058920 View Post
    Patient has struggled with double vision for years. She went to University of Wisconsin where the Doctors were very specific in prescribing her prism. With a slab-off being base down prism, and the doctors asking for prism Up in that eye, will we be safe using the slab-off? The patient has tried a line but refuses to have a line showing, eventhough it is the best way to go .

    That left eye's gonna be awefull thick on the 270, you may want to find a frame that the progressive can fit as high as possible in, something with maybe a 10mm top of the frame to the fitting. The slab off is going to be base down prism the removal of base down prism I should say so it will add to the existing base up rpism, which si why I suggest a frame with a smaller frame top to DRP. To answer your question no it will not effect the prism imbalance in the top, that will remain the same, the imabalnce in the bottom will be corrected so that it is similar to the prescribed imabalance, using a slab off.

  5. #5
    Optimentor Diane's Avatar
    Join Date
    May 2000
    Location
    Jackson, GA - Jonesboro, GA no more
    Occupation
    Dispensing Optician
    Posts
    2,198

    Hmmm

    Quote Originally Posted by HarryChiling View Post
    That left eye's gonna be awefull thick on the 270, you may want to find a frame that the progressive can fit as high as possible in, something with maybe a 10mm top of the frame to the fitting. The slab off is going to be base down prism the removal of base down prism I should say so it will add to the existing base up rpism, which si why I suggest a frame with a smaller frame top to DRP. To answer your question no it will not effect the prism imbalance in the top, that will remain the same, the imabalnce in the bottom will be corrected so that it is similar to the prescribed imabalance, using a slab off.
    I like to draw the lens cross and place the powers accordingly and then move the cross in the direction of the prescribed prism. WOW, then you can get the visualization of how they will look. Then add the slaboff. Graphics help to see what is happening what you will need to do in frame selection.

    Slabbing off the OS will help with the edge thickness, and in using a PAL, Prism thinning will affect it.

    Harry, take my picture and work on it to make it perfect. In the picture, the oval represents an eyewire shape, while the circles around the crosses represent the actual lens. I tried to make them look thinner and thinner where applicable. It would take a long time, and/or I don't have the graphic tools.

    Diane
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	Prism and slaboff in Rx.jpg 
Views:	98 
Size:	47.6 KB 
ID:	5643  
    Anything worth doing is worth doing well.

  6. #6
    Banned
    Join Date
    Jun 2000
    Location
    Only City in the World built over a Volcano
    Occupation
    Dispensing Optician
    Posts
    13,002

    Got nothing to do with the above job

    Anyone notice how the above drawings appear to be 3-D and the black elipses seem to be circular drawing facing out. Differeing amount of face out effect in each.

    Chip

  7. #7
    Optimentor Diane's Avatar
    Join Date
    May 2000
    Location
    Jackson, GA - Jonesboro, GA no more
    Occupation
    Dispensing Optician
    Posts
    2,198
    Quote Originally Posted by chip anderson View Post
    Anyone notice how the above drawings appear to be 3-D and the black elipses seem to be circular drawing facing out. Differeing amount of face out effect in each.

    Chip
    What are you talking about Chip?

    Diane
    Anything worth doing is worth doing well.

  8. #8
    Optimentor Diane's Avatar
    Join Date
    May 2000
    Location
    Jackson, GA - Jonesboro, GA no more
    Occupation
    Dispensing Optician
    Posts
    2,198

    I asked Harry...

    Quote Originally Posted by chip anderson View Post
    Anyone notice how the above drawings appear to be 3-D and the black elipses seem to be circular drawing facing out. Differeing amount of face out effect in each.

    Chip
    but if you think you could fix them, please feel free. Graphics work...

    Diane
    Anything worth doing is worth doing well.

  9. #9
    Banned
    Join Date
    Jun 2000
    Location
    Only City in the World built over a Volcano
    Occupation
    Dispensing Optician
    Posts
    13,002
    Don't think they are broken or bad or anything. Just observed 3-D effect in the drawings. They are great, just interesting. It was more or less a compliment.

    Chip

  10. #10
    Always learning OptiBoard Bronze Supporter
    Join Date
    Jul 2002
    Location
    Wauwatosa Wi
    Occupation
    Dispensing Optician
    Posts
    3,048
    http://www.optiboard.com/forums/showthread.php?t=3538

    In this case the right eye will turn up and in, the left will turn down and in.

    I would consider SV readers or a slabbed (slab-off/bicentric) segmented, especially if there are frequent close tasks. You could probably skip the slab on the PAL if you use separates. Trial frame this if you can. Hopefully the deviation is comitant (the same in all directions of gaze).
    Robert Martellaro
    Roberts Optical Ltd.
    Wauwatosa Wi.
    www.roberts-optical.com
    ~~~~~~~~~~~~~~~~~~
    “Science is a way of trying not to fool yourself"
    -Richard Feynman
    ~~~~~~~~~~~
    A mime-free zone.

  11. #11
    ATO Member OptiBoard Bronze Supporter HarryChiling's Avatar
    Join Date
    Apr 2005
    Location
    Nowhereville
    Occupation
    Other Eyecare-Related Field
    Posts
    7,503
    Blog Entries
    1
    Here's a Chip approved example; I hope. :D The black crosses represent the mechanical centers and the red and blue crosses represent the optical cross aligned with the correct meridians you'll also notice that I placed th optical centers where the prism would place them aproximately anyway. This shoudl give you and indication of how the thickness will play into a prescription such as this. While it's nice to see a visual don't expect Diane to make one for you everytime, or chip to complain about it's loo, or me to make another. ;)

    *I hope no opticians were harmed in the making of this post, all names are made up to protect the innocent or at least the not so guilty.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	example.png 
Views:	66 
Size:	77.5 KB 
ID:	5646  
    Last edited by HarryChiling; 07-22-2009 at 04:31 PM.

  12. #12
    Optimentor Diane's Avatar
    Join Date
    May 2000
    Location
    Jackson, GA - Jonesboro, GA no more
    Occupation
    Dispensing Optician
    Posts
    2,198
    Quote Originally Posted by HarryChiling View Post
    Here's a Chip approved example; I hope. :D The black crosses represent the mechanical centers and the red and blue crosses represent the optical cross aligned with the correct meridians you'll also notice that I placed th optical centers where the prism would place them aproximately anyway. This shoudl give you and indication of how the thickness will play into a prescription such as this. While it's nice to see a visual don't expect Diane to make one for you everytime, or chip to complain about it's loo, or me to make another. ;)

    *I hope no opticians were harmed in the making of this post, all names are made up to protect the innocent or at least the not so guilty.
    LOL:)

    Diane
    Anything worth doing is worth doing well.

  13. #13
    Just An Optician jediron1's Avatar
    Join Date
    Mar 2004
    Location
    USA, New York
    Occupation
    Dispensing Optician
    Posts
    1,727
    Quote Originally Posted by HarryChiling View Post
    That left eye's gonna be awefull thick on the 270, you may want to find a frame that the progressive can fit as high as possible in, something with maybe a 10mm top of the frame to the fitting. The slab off is going to be base down prism the removal of base down prism I should say so it will add to the existing base up rpism, which si why I suggest a frame with a smaller frame top to DRP. To answer your question no it will not effect the prism imbalance in the top, that will remain the same, the imabalnce in the bottom will be corrected so that it is similar to the prescribed imabalance, using a slab off.


    I agree with Harry and William, and Harry is right the left will be very thick.

  14. #14
    Master OptiBoarder
    Join Date
    Jan 2006
    Location
    Central Point
    Occupation
    Optical Laboratory Technician
    Posts
    1,162
    Multiple pairs of S.V. glasses. And sell her a purse to carry them in!

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. Slab off AND prism
    By Mary in forum General Optics and Eyecare Discussion Forum
    Replies: 8
    Last Post: 10-20-2012, 07:55 AM
  2. Free Form & Prescribed Prism
    By Steelerfan in forum Progressive Lens Discussion Forum
    Replies: 15
    Last Post: 08-01-2008, 09:00 AM
  3. Fitting PALs with prescribed prism
    By Jo in forum Ophthalmic Optics
    Replies: 6
    Last Post: 10-28-2006, 01:00 PM
  4. measuring prescribed prism ...
    By mirage2k2 in forum General Optics and Eyecare Discussion Forum
    Replies: 9
    Last Post: 04-26-2006, 10:34 PM
  5. Slab-off Prism
    By Neophyte Optician in forum Ophthalmic Optics
    Replies: 11
    Last Post: 04-24-2006, 01:29 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
  •  
OptiBoard is proudly sponsored by:
Identity Optical, Younger Optics, Carl Zeiss Vision, Vision Systems, Inc. and Chemistrie Eyewear