Can anyone give some suggestion for Anisometropia In PALs , which can of design or PALs suitable for this kind of patient?
Can anyone give some suggestion for Anisometropia In PALs , which can of design or PALs suitable for this kind of patient?
it really depends on the VA's
a short corridor progressive will be the obvious option, as will a individualised design
Hi,
You can slab off a progressive for an anisometropic presbyope just as you would slab off a FT bifocal for them.
There are some rules of thumb as to where to slab...not necessarilly at the PRP or at the near seg area, but in between the two. You will probably want to consult your lab on where to begin the bicentric grinding. While the patient may not love the fact that there would be a line in one lens, they would at least be able to have binocular vision for near.
PALs are not currently designed to offset vertical imbalance at near issues to to aniso or antimetropia combined with presbyopia. Not even current technologies such as freeform.
Hope this helps,
: )
Laurie
Can someone please explain the benefits of slab off progressives vs. segmented MF?
Hi Dr. K,
I would say that it is very subjective...
Personally, I would prefer a PAL over a FT for many of the same reasons regardless of vertical imbalance at near issues. That is, the intermediate area, the multiple focal lengths, the enhancement to ergonomics while working (not as much head tilting), the cosmetics (although there would be a slight line in one lens, it would still look better than a segmented multifocal).
I am hopeful that most people choose PALs for the optical benefits, not just cosmetics (optimistic, I know)...the optical benefits are the same with or w/o the slab component.
: )
Laurie
I have done slab offs on progressives. My sister in law wears a slab off in her Varilux Panamics 1.60. The line is slight and not that noticable.
without the RX this is academic. BTW at what degree of aneisemetropia would you guys consider a slab off?
did the slab off line is obvious? besides slab off, stil hav any idea for anisometropia patient?Originally Posted by Happylady
Hi,
The "textbook" criteria is when there is an optical difference of 1.50 D or more between the eyes in the 90 degree meridian.
I think 1.50 is subjective...I would not necessarily go to slab off at that point. I would use 2.00 D as a criteria. I have ordered tons of slab off over the years...automatically when the optical difference at 90 is 2.00 D or more. And, I would also recommend calling the prescribing doctor out of courtesy, to be sure there are no contraindications to use slab off. Personally, I have never had a doctor say no, but I still call just to be sure.
: )
Laurie
that explains why I feel some are slab off triger happy - I only do a slab off when the patient starts to notice they are struggling with a rx, I often find that patients with 4D vertical aneisemetropia are fine with no slab-off... I put this down to the fact that basically they are used to it without
In regard to waiting for the patient to complain:
I am not sure they even know that they are struggling with Asthenopia or Suppression. Some patients think they see a slight "shadow" above printed words, when it is really vertical diplopia. My guess is that, if they are not complaining, they are suppressing vision in one eye at near. And, if the suppression is constant, they won't notice as much as if it were intermittant.
My understanding is that, while we can fuse disparate corresponding points on the retina, the amount we can fuse binocularly/vertically breaks at around 2.00 D. Grosvenor speaks to this in his text "Primary Care Optometry" in great extent, including horopter measurements and Panum's Fusional Area...where we can accept for horizontal non-corresponding points much better than vertical.
Years ago, I worked for an amazingly great optician in Portland, Maine, Wolfgang Liese. He is one of the brightest opticians I have had the pleasure to work with, and a great mentor. I follow his philosophy that, at the very least, it is very difficult/almost impossible to comfortably fuse more than 2.00 Diopters of optical difference in the 90th degree meridian. We slabbed a ton of patients, with no problems. If they didn't need it, wouldn't there have been subjective complaints when we put it in?
: )
Laurie
[QUOTE=hardbox_happy]Can anyone give some suggestion for Anisometropia In PALs , which can of design or PALs suitable for this kind of patient?
I think we should classify the type of anisometropia , axial or refractive or both , because there will be some different problems about aniseikonia , binocular vision and lenses base curves , when they wear single lenses before they have got presbiopia.
My team and I have studied base down prism from prism reference point and reading area. We try to find out pattern of prismatic effect in PALs design when distance powers are plano , plus , high plus, minus, high minus, astigmatism, high astigmatism of every lenses series especialy laboratory lenses.If somone knows the papers about this topic, please tell me . Thank you.
Progressive blended prism's thats what we need! where's that free form generator software? I need to flex my programming fingers.
That is progressivley more prism as you look down!
You read it here first!
All the pediatric OMD's I know say: use an exec whey applicable, otherwise use ST45 . These they say use only and split the pupil with them..
No progressives ever in amblyopia! Of course there is more money in progressives and "the poor childs self~esteem" won't be as offended in
progressives. It won't be the best thing to do for the amblyopia, but lets make more money and let the child's self~esteem be maintained even if his eye stays crossed.
Chip
Chip..........if any Chiropractor ever starts watching those threads he will send his back- and sore bone parients to wear progressive lenses because they might help cure these problems too...................
:bbg:
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