Results 1 to 7 of 7

Thread: Add power in the distacne area of progressive lenses

  1. #1
    OptiBoard Novice
    Join Date
    Jan 2017
    Location
    Iowa
    Occupation
    Dispensing Optician
    Posts
    8

    Add power in the distacne area of progressive lenses

    I am fitting and dispensing at a new job. I have had a few patients complain that the distance is is blurry on their progressives. I have set the fitting cross to line up 1 or 2 mm below center of the pupil. The patient can see clear distance when looking looking 5mm above the fitting cross. I see the same thing in the lensometer. The distance is well above the fitting cross. At the fitting cross you are already getting well into the add power... I started fitting new patients lower, but i don't think I should have to compensate 5mm. Any Ideas? Am I doing something wrong? I think there might be a problem at the lab with their "in house brand" progressives, but I want to make sure I know what to say technically to describe the problem. Does anyone have advice? I have not had this problem before working for other companies.

  2. #2
    OptiBoardaholic
    Join Date
    Apr 2012
    Location
    USA
    Occupation
    Dispensing Optician
    Posts
    236
    Are you sure of where the fitting cross is relative to the 180 for this particular house pal? I've had misinformation given before but I would check there for sure.

  3. #3
    OptiBoard Novice
    Join Date
    Jan 2017
    Location
    Iowa
    Occupation
    Dispensing Optician
    Posts
    8
    The fitting cross is 4mm above the MRP marking. Should there be any of the ADD power right at the fitting cross? If so, how much? How do I tell if the progression is starting too high up on the lens? What kind of surfacing error might cause this? Is it incorrect surface blocking? The laser marking is a star. I'm guessing its a Chinese import.

  4. #4
    Master OptiBoarder OptiBoard Silver Supporter
    Join Date
    Jul 2008
    Location
    Cincinnati
    Occupation
    Other Optical Manufacturer or Vendor
    Posts
    637
    Quote Originally Posted by pizzamouthburn View Post
    I am fitting and dispensing at a new job. I have had a few patients complain that the distance is is blurry on their progressives. I have set the fitting cross to line up 1 or 2 mm below center of the pupil. The patient can see clear distance when looking looking 5mm above the fitting cross. I see the same thing in the lensometer. The distance is well above the fitting cross. At the fitting cross you are already getting well into the add power... I started fitting new patients lower, but i don't think I should have to compensate 5mm. Any Ideas? Am I doing something wrong? I think there might be a problem at the lab with their "in house brand" progressives, but I want to make sure I know what to say technically to describe the problem. Does anyone have advice? I have not had this problem before working for other companies.
    Depends on the size of the reticule on your lensmeter. I usually measure about 4mm above the cross.

  5. #5
    One eye sees, the other feels OptiBoard Silver Supporter
    Join Date
    Jul 2002
    Location
    Wauwatosa Wi
    Occupation
    Dispensing Optician
    Posts
    5,458
    Quote Originally Posted by Don Gilman View Post
    Depends on the size of the reticule on your lensmeter. I usually measure about 4mm above the cross.
    Yup, that's the distance reference point, usually 4mm to 6mm above the fitting cross, depending on the manufacturer. This is where the distance power should be measured for progressive addition lenses.

    As far as seeing blur from the wearer's perspective, if the fitting cross bisects the corneal reflex in the primary gaze position, the clearest distance vision should occur when looking at an object level with the eyes, at optical infinity, without posturing. Blurring at this point is usually due to poor lens design, but unusually large pupils and/or high adds might cause problems with all but the very best/appropriate PAL designs.

    Hope this helps,

    Robert Martellaro
    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.



  6. #6
    OptiBoard Novice
    Join Date
    Jan 2018
    Location
    Canada
    Occupation
    Dispensing Optician
    Posts
    1
    These sound more like office lenses than dedicated PALS. Did they give you any fitting charts that layout the corridor and the drop is is this more of a, this is what they told me situation?

  7. #7
    OptiWizard
    Join Date
    Sep 2012
    Location
    West Scranton, Pa
    Occupation
    Dispensing Optician
    Posts
    329
    Careful not to look up at the patient when measuring seg height and note their normal posture. If they carry ther head back normally you should compensate lower on segs.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. Evaluate Near power or ADD power for Freeform products?
    By Delly in forum Progressive Lens Discussion Forum
    Replies: 3
    Last Post: 08-16-2011, 12:53 PM
  2. Add Power question
    By gogetter in forum General Optics and Eyecare Discussion Forum
    Replies: 13
    Last Post: 10-14-2010, 03:08 PM
  3. +3.25 add power polarized progressive?
    By Jimdayok in forum General Optics and Eyecare Discussion Forum
    Replies: 1
    Last Post: 01-13-2005, 04:17 PM
  4. UK Opticians and Add Power
    By Darryl Meister in forum General Optics and Eyecare Discussion Forum
    Replies: 11
    Last Post: 03-19-2003, 05:49 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
  •