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Thread: Varilux Progressive

  1. #1
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    Confused Varilux Progressive

    Prescription:

    OD -8.25 -2.00 x 010
    OS -8.50 -1.25 x 150
    ADD +2.00

    Varilux Panamic with Crizal Alize, high index 1.74

    Patient past wearer of Panamics for 5 years. Now experiencing blurry in intermediate vision with new glasses - previous glasses were clear. Previous prescription:

    OD -7.75 -2.25 x 105
    OS -8.50 -0.75 x 70

    When patient holds glasses out from face about 1/2" (maybe less) intermediate and reading vision becomes very clear. This is odd since usually decreasing the vertex diminishes all aberrations but in this case increasing the vertex is making things clearer. It is the same when she pulls the glasses down on her nose about 1/2". (No distant problems when glasses are worn normally.)

    Her main complaint is computer vision. But, when she sits at 2 arm's lengths from the computer, vision becomes rather clear. This seems to tell me that intermediate vision is too strong. Would this suggest that the intermediate area needs to be raised?

    Thanks for any help!

  2. #2
    One eye sees, the other feels OptiBoard Silver Supporter
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    That's due to the Rx change (more minus). I show my clients how much better the distance vision is with the new Rx and explain that we have to take away a little intermediate utility to improve the distance. It's a good idea to mention this at the time of the order, showing the difference in vision with flippers or trial lenses, preparing the client for the inevitable, as well as the possible need for computer glasses.

    By the way, check the cyl axis, might be a transposition error when you posted the Rxs.

    Regards,
    Last edited by Robert Martellaro; 12-18-2006 at 04:27 PM.
    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.



  3. #3
    Allen Weatherby
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    Rx?

    [QUOTE]Prescription:

    OD -8.25 -2.00 x 010
    OS -8.50 -1.25 x 150
    ADD +2.00

    Varilux Panamic with Crizal Alize, high index 1.74

    Patient past wearer of Panamics for 5 years. Now experiencing blurry in intermediate vision with new glasses - previous glasses were clear. Previous prescription:

    OD -7.75 -2.25 x 105
    OS -8.50 -0.75 x 70
    [QUOTE]

    Have a Dr. recheck on this Rx. THe cylinder change is significant. The right eye total power is only 0.25 change and the 0.50 change but the axis of the cylinder maybe wrong in old or the new. If the cylinder is changed that much the vision will be different especially in the narrow transition from far to near.

    Was the add the same before?

  4. #4
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    Sorry about the cylinder - I was looking directly at the old prescription (from a MD) and forgot to do the conversion between M.D. and O.D., the old presc. should read:

    OD -7.75 -2.25 x 015
    OS -8.50 -0.75 x 160
    ADD +1.50

    I agree - not much difference between Rx. Would .50 increase in ADD cause the blurry intermediate?

    It's sometimes difficult to prepare patients for the possibility that they may need progressive computer glasses along with their normal PALs since they are already shelling out high $$$.

    The only other thing I can think that might be making a difference is that the patient's old glasses (5 yrs. ago) were a bit larger than her current ones - more room for the intermediate area? Let's face it, most of the frames these days are small and smaller.

    Thanks - appreciating the help.

  5. #5
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    I found the below information while doing some research (this was an answer to another problem that sounded almost exactly like the one I described in my original note).

    Opinions?

    This is rather unusual. In effect, you are making your ADD stronger by increasing vertex (since plus power becomes stronger as vertex increases). I would suggest having your eye care professional hold a +0.25 single vision lens in front of the eyes when you are looking at intermediate to see if this improves things. If it does, the ADD power could be increased by either +0.25 or +0.50 (since at intermediate will only get 50% of any increase).

    Other than that, they could try a duochrome test at near when you are wearing your glasses at the normal location vs. when you wear them down your nose.

  6. #6
    Allen Weatherby
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    Try an individualized PAL for patients like this

    EagleEye123:

    The width of the channel will be narrower with the increase in the add. What would work great for this patient, (yes I am talking about a product we produce), is our individualized digitally surfaced ICE-TECH PAL. This product will give the patient a greater widith in the intermediate and remove all most all of the abberations caused by the cylinder in the right eye.

    As far as add and vertex distance goes, in the US we have been placing people in Rx's with the prescribed add, but as your comment points out an increase in vertex distance increases the add. So the lower placement of the add is actually a higher power than prescribed in the "as worn position". For people that are already in a PAL you should keep them in the over add mode. They will feel like there is a problem if you give them the prescribed add in the as worn position after having been wearing over powered near in previous Rx's.

  7. #7
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    How long has the patient had the new glasses? How long was she wearing her old rx? Does she do primarily do near vision work everyday?


    Just curious on those things.

  8. #8
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    The patient has had the new glasses for about 1 month now and had her old Rx for 5 years - which were Panamic (which is the lens we switched to). With the old Rx and frames had no trouble with intermediate vision. (Old frames broke or else I think she would still have them.)

    She said that if it were not for the computer, that the new glasses would be "okay" but she does do computer work along with reading while doing computer work...not a full 8 hours/day but more like part-time.

    She sat at one of our computers and had to raise her head up a good inch or two in order to focus at arm's length.

  9. #9
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    Let's go back 5 years. Add was +1.50, leaving a reserve accommodation of about +1.00 to +1.50. That, plus depth of focus, made it possible for her to see the screen through the distance portion of the glasses. What has happened since then? She has definitely become more presbyopic, with accommodation down to about +.75. Depending on the screen distance and pupil diameter that's usually not enough to get good focus at intermediate distances.

    Why didn't she notice this with the old glasses? Well, something else happened along the way to her becoming more presbyopic, she also become more myopic, giving her and extra +.37 and +.25 to assist her near and intermediate vision in the right and left eye respectively. The increase in myopia was probably coincident with her advancing presbyopia, essentially masking the loss of near and intermediate vision.

    Computer glasses don't need to be expensive- an un-coated ST28 in a very inexpensive frame should retail around $100. Alternatively she might do OK using the old glasses for comp work until the presbyopia advances further or the work conditions change.

    Hope this helps,
    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.



  10. #10
    OptiBoard Apprentice macularry's Avatar
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    Custom Tailor Your Computer Lenses

    I prescribe a custom lens for my patients. I use their age, height and monitor distance to configure the lens. Most computer lenses put a standard amount of additional plus in the distance or intermediate area. This works for some people, but is hit and miss at best. You can use any type of progressive once you have determined the proper power distribution. This will give 600% more computer viewing area.

    Someone who is 6'1" as opposed to 5"1 will require up to .5 diopter difference in the computer viewing area, even if all other components of the "general use" prescription are the same. This is not taught in most schools.

    In addition age is a factor. Someone who is 40 as opposed to 50 will require less plus because the same person at age 40 has more accommodation than when they are 50.

    I use an algorithm that I created to configure the prescription for computer use. Anyone who uses the computer for more than 1 hour continuously is cheating their vision and work performance by using general use glasses. Even worse, wear monovision contacts at the computer for extended periods of intense computer use. In this case one eye is focused at optical infinity(20 feet) and the other is focused at 16 inches. Most experts recommend a minimum monitor distance of 22 inches. The algorithm can configure a computer prescription for this situation as well.

    If you would like to use the algorithm, shoot me an email:

    DrLarryTarrant@aol.com
    Last edited by macularry; 12-19-2006 at 05:06 PM. Reason: misspell

  11. #11
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    Thanks - Dr. Larry....I have forwarded your offer to the patient I have been talking about so that she can take this information with her on her next appointment.

  12. #12
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    Quote Originally Posted by macularry View Post
    I prescribe a custom lens for my patients. I use their age, height and monitor distance to configure the lens. Most computer lenses put a standard amount of additional plus in the distance or intermediate area. This works for some people, but is hit and miss at best. You can use any type of progressive once you have determined the proper power distribution. This will give 600% more computer viewing area.
    Larry,

    That's been my experience also, for both focal length accuracy and in regards to field of vision. I tried one of the "office" lenses- I had to put -.50 over to see the screen clearly, with the text blurring slightly with lateral and vertical head movements.

    Someone who is 6'1" as opposed to 5"1 will require up to .5 diopter difference in the computer viewing area, even if all other components of the "general use" prescription are the same. This is not taught in most schools.
    Could you explain this in more detail? I would expect that a taller person would have a longer distance to the desktop as well as a greater reading angle, but if the monitor is adjusted to the proper vertical height there should be no further adjustment required for the eye level work distance due to the client's body height.

    I use an algorithm that I created to configure the prescription for computer use.
    That sounds faster than using a trial frame, but wouldn't refracting the work distance tend to be more accurate?

    Regards,
    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.



  13. #13
    OptiBoard Apprentice macularry's Avatar
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    Robert,

    Although a patient will give a monitor working distance, most people are not stationary over a 2 hour period. The taller the individual, the more range they will have to gravitate away from the monitor. DaVinci came up with Vitruvian Theory, which states that one's wing span is equal to one's height and one's eblow to fingertip distance is equal to 1/4 one's height. This will not be exact to the millimeter with every individual, but it holds true for purposes here.

    If you will send me your email address, I will give you more information and some helpful illustrations that will be useful when explaining this to patients.

    Hope this helps,

    Larry

    DrLarryTarrant@aol.com

  14. #14
    One eye sees, the other feels OptiBoard Silver Supporter
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    Larry,

    robopt@damnspam.com

    Replace "damnspam" with "execpc".

    Vitruvian Theory is useful when painting, where optics, although a pure science, is not to be applied exactly. However, we are dealing with the human brain to some extent, so I'll keep an open mind.;)

    Thanks.
    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.



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