Can you tell me more, you have me rather excited!!!! How many corridor lengths does it come in?Originally Posted by john-atlanta
Can you tell me more, you have me rather excited!!!! How many corridor lengths does it come in?
11, 13, 15, 18 in the fixed design. Variable (my lens of choice) 11 and UP.
The power of this lens is not just the variable corridor length, but the "as worn" technology, the fact that they account for the frame shape in the design ("FreeFrame Technology") and the remarkable, astonishingly low level of distortion compared to others I have worn.
I HIGHLY recommend this lens.
Maybe Laurie could provide more detail. Laurie to the forum, LAURIE TO THE FORUM PLEASE!!! :bbg:
I guess it has nothing to do with lens design.
I have got the same complaints from young hyperopes(40-48) who has distant power over +1.00 ,since I encreased the Addition.
As they are used to the old Pals with low Add, wearing eyeglasses high up on the nose for more magnification does not cause so much discomfort. So he does for reading but he also gains wider intermediate distance.
What I usually did is to reduce distant power 0.25-0.5 D from the new prescription, Increase the Addtion 0.25 or keep the same if he does not do close work,widen the pd 0.50-1mm each side and place the fitting point 2-4mm. higher than the eye point.
Then adjust the frames to sit close to the face.
But this does not work if he is over 52 or the Addition is up to 2.25D.
He might not get the best out of Pals but it fits his needs.
...I was busy in the shoe section, ; )
Two thoughts:
Catagory I: Multi-use PAL
Catagory II: Wide Intermediate Range, suitable for long hours w/computer.
Catagory I:
Autograph II can be ordered in Fixed, where the 'corridor', or 'transitional zone' in the vertical is fixed. You can fit a fixed 11 at 11mm, for example, and the corridor/transitional area will be fixed. If you choose to fit the fixed higher (11mm fixed at 15, for example), you will not change the Intermediate, but will add to the amount of reading area in the vertical.
Autograph Variable: The corridor/transitional area/intermediate will vary, depending on seg height. A rule of thumb, is you will have approx. 5mm of reading area in the vertical meridian (i.e. no cutting off adds), and the length of the intermediate will vary in length.
A quick tip:
Fixed: when you want to have clear control over the amt. of vertical mm of each zone: A bifocal convert, for example, will enjoy getting to the add right away, and can have more depth in their reading area.
Variable: new presbyopes, and dispensers who don't feel comfortable, or a need to maniupulate the parameters. The computer default will ensure that approx. 5mm full reading in the vertical meridian will exist, and contour the design based on additional information. Running parameters through additional software will keep within design criteria, as I mentioned in a previous post.
Finally,
Catagory II:
It is my opinion that, if a client is spending ample time at the computer, they need occupational lenses. The Shamir Office Lens comes in two catagories as well:
Catagory I:
Molded front surface (digital mold, not ceramic-to-glass mold), traditionally surfaced back curves. The lens begins at total near power, and 'digresses' out to around 10-13 feet, depending on Add power. There are four 'dynamic powers' to choose from (how much regression, or deduction of plus towards the top)....I would let the lab choose, unless you have very specific working distance requests outside the norms...the 'top part' of the lens ends up being over-plussed by around +0.50 - +0.75 D, they are not meant to yield 20 ft. vision. By dumping the idea of 20 ft. focus, they gain the widest intermediate, edge-to-edge.
Order like a regular PAL...distance Rx and Add power, mono PD's, and mono fitting cross heights, center pupil.
Catagory II:
Office/Autograph II: this is a design that is custom manipulated per Rx. It is generated via freeform, entirely on the back surface. There are unlimited amounts of 'dynamic powers'/'digression of plus power' towards the top, with the Rx parameters run through 'eyepoint technology' (ray-tracing system), and 'freeframe technology' considers additional information, like the exact positioning of the lower eyewire under the pupil, not just the boxed 'B' dimension. It is best to send the frame to the freeform lab to digitally trace it beforehand.
In addition, you can give additional 'as-worn' measurements: distance to computer, angle of monitor above or below line of sight, designate sitting or standing, ect. Again, the computer software will default to norms if this info is not given.
These new technologies are evolving at a fast rate...alot to keep up with!
Hope this helps,
: )
Laurie
(incase I haven't 'disclosed' in a while, in addition to teaching optics full time 'GO HCC!'), I give CE's for Shamir.
I always push for the Definity pal, with the patients. Not once have I had a Non-adapt. None of us @ the office have. I put my mom in it @ she loves it! I am glad to see people talking about it.
Great post! Does the new freeform office have the same requirements for fitting height ABOVE the pupils as the original office lens? I have yet to incorporate the office style lenses into my practice and would love some feedback from the big brains on this board!
The fitting height should be center pupil, regardless if it is the original (digital molded) or the Autograph II in freeform.Does the new freeform office have the same requirements for fitting height ABOVE the pupils as the original office lens?
John-Atlanta,
I know that you are in the presbyope club, as you mentioned wearing various PALs...
I would suggest your trying out an office lens...it is great for your work environment too!
: )
Laurie
(PS: I will PM you with status of the other project we talked about in regard to a plot on your Element lenses)...
bumping to this to the top. I have a patient who is a nurse working at podium desktops with the monitor at eye level. She needs a full-time non-occupational progressive which will give her a high and tall intermediate. I started her with a Comfort DRX and vision is good but intermediate height is too low.
Any thoughts? DRX short?
I'll add that this is a redo through VSP choice unfortunately so some limtations do apply
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In that case I would use a shortened corridor (a short(er) fit design DRX short would be fine) and back the add off, personally - she will be using the "near" portion on the computer but will be holding things further out to "read" as a trade off. But a progressive is a poor choice for her if she is having that much difficulty. Either try an office lens that gives up to 16-20ft of distance vision or a good'ol FT35
What if the patient convergence does not match the progressive design defaults?
Does that give the patient the feeling of a narrower corridor?
How usual could this be?
Certain situations can be solved through ergonomics, especially for those that refuse (for whatever reason) a task specific pair of glasses. Some patients can have improvement with an elivated chair. With this patient, see if she can put one of those workout steps at her standing work station. If she can elivated herself 4-5 inches it may make a big difference.
Great question!
Less than 2% of patients have a convergence that matches the 5mm default inset. Most of our progressive patients have decreased near width and unwanted lateral prism (which creates eyestrain). Most Free-form lenes follow the standard 5mm inset of traditional grinders, and use a corridor designed for low power myopes.
There are only a few lenses that address this, the Seiko: Surmount and Superior (to a lesser degree the Supernal), The Ziess Inidividual 2, and the Rodenstock Impression (not available in the US at the moment).
Near PD is the most important POW measurement, not only does it place the reading zone where is should be, I can if I am smart, realign the whole corridor to account for eyepath. This is done by using a combination of RX and near PD to estimate the Axial length of the eye. Knowing the axial length I can improve Ray Tracing, this near PD can also improve distance zones.
The Seiko Surmount is the only reverse geometry lens available right now. It flips the corridor to put the wide end toward the pupil, thus making the intermediate the widest portion of the lens. Its not edge to edge clear in the distance, but its pretty good. The Comfort is a reading emphasized design in all its flavors, the Intermediate will always be narrow. I can never turn a wrench into a screw driver even if I cut it in half. A short design will make her issues worse.
Use the Surmount WS version for add 2.00 and greater. Order with near PD. Fit on Center (don't drop). You will be golden.
If 2% are the ones that match the 5mm inset, it would be interesting to see percentage according to mm of mismatch.
Is there any study about this that you know?
If the DRX short is like the Physio short, which is more of a medium corridor, it might not be short enough to minimize posturing sufficiently. I'm not sure what's available with VSP so look for a design that has a fixed corridor length and a minimum fitting height of 14mm or so.
Note Tallboy's recommendation of cutting the add to minimize rubbernecking.
Modern PALs vary the inset according to base curve or distance Rx, less inset for minus power and more for plus power. The only default I'm aware of is a 40cm work distance that requires a near PD value equal to about 94% of the distance PD, if there is no power at 180. All bets are off if there is a fixation disparity or a habitual head turn.
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.
I'm still not buying into this stuff.
1. Convergence is entirely dependent on reading distance. It can't "vary". (Similar to "stimulus AC/A" for those so inclined.)
2. If people like a longer reading distance, this needs addressed in the prescribing phase...lower add power.
3. Fixation disparities/phorias are addressed by prism, not fancy inset/outset. ("Response AC/A for those so inclined). (I mean it's possible, but that's crazy. Near phoria would have to be a parameter on the individualized design, and even so the prismatic effect of variable inset is minimal for most lens powers. Right?)
4. I have no idea of what sharpstick777 is talking about re: axial length and convergence unless he's going to tell me about ocular centers of rotation etc. which sounds to me like angels dancing on the head of a pin. But he knows his stuff.
Minimal for most. But if the IPD is unusually narrow, the power is higher plus, and the add is over +2.50, the combined error can be consequential, especially as the eyes track through the narrow corridor near the blur boundaries. Remember this thread? PAL / PD Issue Thread.
WRT Seiko lenses, here are Seiko's own astigmatism plots. The lack of horizontal symmetry implies a somewhat older fundamental PAL design, although some of the asymmetry is truncated when cut and edged, except with larger frames.
http://plasticplus.ca/wp-content/upl...t07601_4pg.pdf
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.
Hey, that's not an inverted pyramid...it's an hourglass.
Is it less hourglassy and more rectangular? It ain't no "V".
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