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Thread: curved lne

  1. #1
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    curved lne

    Dear all

    Previous Rx (rodenstock life2-non freeform lens)
    OD= S+0.50 C-0.25x071 ADD+2.50
    OS= S+0.25 C-0.25x101 ADD+2.50
    PD=32/33

    Dispensed Rx (rodenstock lifefree colormatic grey 1.54)
    OD= S+1.00 C-0.25x090 ADD+3.00
    OS= S+0.75 C-0.25x090 ADD+3.00
    PD=32/33

    4 years from previous to current Rx. Progressive lover

    Previous Rx has no problem except the distant is not as sharp, near also not as sharp
    When the dispensed Rx was worn, the distant is very OK, and so does the near EXCEPT when he looked at straight line (especially ruler), it somehow is not a straight line, but more like bent curve. He's an architect and it's quite bothersome for him (I'm sure).

    Was my lens choice wrong? was the addition too high? Tried to adjust the fitting multiple ways, even changed the pantoscopic tilt and vertex distance. Still doesn't work. Rest assured the Rx is correct. Thx

  2. #2
    Compulsive Truthteller OptiBoard Gold Supporter Uncle Fester's Avatar
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    That's a lot of add for the near.

    My thought is that amount of power change has affected the curve of the lenses especially at near. When he's looking through the lens by the time the image of the line is hitting the retina it seems distorted to what his retina has been used to seeing.

    Usually this will go away after some time. How long we cannot say.

    I'm inclined to say near should be cut back by .50 but I'd like to hear from someone else to verify this is the problem.

    Vertex distance in this power is too small to matter.

    Maybe he could create a new design in his drawings. Kind of like Picasso! (kidding)
    Last edited by Uncle Fester; 03-08-2013 at 09:57 AM. Reason: tweak...

  3. #3
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    @opto: Was the base curve supplied, changed from previous?

    Suggest backing off the Rx change to a lesser amount. The person is dealing with a diopter of plus added(od) to Rx since last change.

    Institute the change over several lenses.....or default to a FT35 trifocal for occupational purposes!
    Eyes wide open

  4. #4
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    @ UNCUT

    Hmm, good point on the base curve issue. The previous lens has been worn 4 years and it was not even the freeform lens generation. I didnt bother checking on the BC, but if the near is affected then the distant would be as well, no? From my experience in the past, change in BC affects overall coziness of the lens and not just the reading especially a bent line. but a good point

  5. #5
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    @ Fester

    The curved line still there after 2 weeks, the weird thing is that it is only that straight matter that is distorted, everything else for reading letters, numbers are OK :D

    I wonder if he's playing with me. I get that all the time, customers wanting services. Fiuhh

  6. #6
    OptiWizard
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    Architect is gonna love his intermediate. Ever consider a task-specific lens for work - especially with a +3.00 add? Shamir office or Sola Access? Just a suggestion.

  7. #7
    Compulsive Truthteller OptiBoard Gold Supporter Uncle Fester's Avatar
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    I do not think they are making this up.

    Try this experiment-

    Maybe draw 3 or four straight horizontal lines on a couple of pieces of paper. Then tape together so they form a long scroll. Hold the sheets at an angle away from the patient like you would hold a newspaper so there's several distances from 1/3 of a meter out to a meter. When they look through the lens is the curve present at all times? That would probably be base curve.

    If it is only when looking through the near then I'd say it's too much add.

  8. #8
    Master OptiBoarder optical24/7's Avatar
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    Higher adds = narrower corridor and near area. +3.00 is very narrow in any design. I agree with others who have said drop the add back to a +2.50

  9. #9
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    Or use a dual-surface design to manage the add! I would bet the Hoya ID would solve the issue.

  10. #10
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    Curious - would not the 1 diopter increase at near be sufficient cause for some spatial distortion by itself? Dunno if the relative fitting heights are similar, or what the working distance may be ... but presumable he will be into more plus power earlier in the lens.
    Trip

  11. #11
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    I agree, Trip.......and welcome to the Forum, from a Canuck ECP.

    A multifocal contact lens would reduce the phenomena, but introduce some other inconveniences.
    Eyes wide open

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