I have a patient who I have had in comforts for yrs, with no problems. She's high index transitions. She now has a small change in Rx, all of her previous Rx,s have been at least 22 H. her new frame is semi rimless I can go 19 maybe 20 tops. I hate to cut off any add over her pevious which was a 2.50. Would a creation work just as well? It also comes 160 trans, and goes 19 H?
Comfort was originally designed (marketed) with a minimum seg ht of 21. Put it on the cutout chart and look at what is being lost in edging.
The minimum height suggested for Comfort is 18. I never have a problem with them at 18 high.
I, also have not had a problem dispensing many, many comforts at 18.
I'm worried she will compare her old ones at 22 high against her new ones at 19 high and be dissatisfied with her improvement. Thus maybe its time to try a new lens
I'm not saying that it couldn't be done. I just question why the minimum fitting height went from 21 to 18 about the same time that AO Compact made it's appearance.
Don't forget that if you try the comfort at 19/20 and it doesn't work for you, the nonadapt warranty will allow you to go to a short corridor at no charge to you (except the difference in cost) so explain that to your patient and give it a try!
Good luck!
The Comfort has 85% of the add power at 12.4mm, and probably close to 100% at 15mm. Should be OK if she's not uncomfortably aware of the bottom of the lens/frame. You might want to measure her reading angle/depth. An avid reader might be more comfortable with a shorter corridor along the lines of the Piccolo, Concise, XS, or Ellipse.Originally Posted by Echo419
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.
Echo419,
Best thing to do is what Judy has posted. Put it on the cut-out chart and see if all the reading and distance fits...
I've never gone by just a number!!!
18 mm. is minimum fitting but ...
20 mm. is recommend fitting but ...
22 mm. is optimum fitting
I have a chart that says minimum fitting height is 23....
and one that says 22...
and one that says 19...
and they are all Comfort charts...
The lens never changed, so why the differences? The answer, according to the evil empire themselves, is "The definition of what works has changed. It used to be that a person needed 100% of the add power. We have found that now, people only NEED 85% of the add power. When you fit a Comfort at 19 high, you get 85%, which is adequate for most people."
You lose 15% of the add, according to the Evil Empire's tech guys.
So, I have a question, and will post it in another thread for those who want to discuss it...
If it is perfectly OK to knowingly fit and dispense lenses which give the wearer only 85% of the prescribed power for reading, why can't we intentionally do the same for any and all Rx's? I'm gonna open up "Close Enough Optical". We'll do a commercial playing on the movie "Mr. Mom".
Patient: Whatcha puttin in, 20/20?
Me: 20/20, 20/40- whatever we make!
Vip and Xl lenses had the same changes....Fist 24mm Min, Then 22, Now down to 18! So the lens did not change, just the lens company and there thoughts on selling..oops I meant fiitting their lenses!
Without getting too conspiratorial, my thought was they might have kept the same design, but the lens that was sold as a +2.25 started getting marked +2.00, and so on up and down the line.
Of course, if you go look at the UK Site, you'll see a "Comfort Small" sold alongside the Comfort. Perhaps it got redesigned, in either the way I suggested (or not), and we just got what they call the Comfort Small, but instead just replaced all our Comforts with it.
Close...
They basically move the markings. For instance, Hoya has a "short corridor" lens, supposedly. It really is the same as their standard, with the markings shifted up 2-3 MM. That means you get into the corridor quicker; ever wonder why your patient says the distance isn't as good?
However, as much as I hate saying this...
The Ellipse is really a short corridor lens, and a pretty good one, because it really is a short. Back to the matter at hand, which is the fitting height which "magically" changed... it's just a matter of "what works" instead of what's best.
Close Enough Optical- I'm tellin' ya- the time has come.
Absolutely untrue.For instance, Hoya has a "short corridor" lens, supposedly. It really is the same as their standard, with the markings shifted up 2-3 MM.
RT
Minimum Fitting Height of Comfort is 17 mm.
Please read page 13 of
" Progressive addition lenses—
matching the specific lens to patient needs " , by Dr.
James E. Sheedy, O.D., Ph.D.
http://optometry.osu.edu/COOR/pdfs/O...SciArticle.pdf
On page 13 of this article , Comfort at fitting height 18 mm have rating for near zone 26.6 , 22 mm = 56.9 and 26 mm = 80.1
, compare with Varilu_ Panami_ - 18 mm = 21.6 , 22 mm = 42.6 and 26 mm = 56.4.
Comfort have better rating for near zone , because Comfort is harder design than Varilu_ Panami_.
In Thailand , many of Comfort wearer was unhappy when they switching to Varilu_ Panami_.
The complaint is less sharp vision at near and when reading 20/20 at 40 cm is narrow than Comfort.
In case that you have to going for 19 mm fitting height for Comfort wearer , please going for Nikon Presio i-13 that better than Varilu_ Ipse_ for myope.
After fitting more than 10,000 of PALs , my openion is " do not beleive what the PALs's company say " , because they will inform you only some truth and not inform you about the dark side of their product.
Every PALs have good side and dark side , please pay attention to your patients , because your patients always tell you the truth.
I will show you many fact of PALs in my website on December 2006 at www.apcthai.com ( English version ).
In Thailand , many PALs's company are liers. I hope in the PALs 's company in Europe and North America are much better than Thailand.
Sometime , the O.D. & optiker have to be Jedi's Knight who will be the new hope for presbyopes. Our mission is to protect our patient from the PALs's Empire who try to sell low quality PALs in very expensive price.
We have to protect the investment of our patient! , because the patient is the king and we are the PALs's Knight.
" Life is too short to limit your vision"
ISOPTIK : The Hi-End Eyeglasses Centre
494 ERAWAN BANGKOK 4th floor
Ratchaprasong , Bangkok , Thailand 10330
isoptik@gmail.com
www.isoptik.com
Hotline & SMS : +66 81 538-4200
Fax. : +66 2 251-3770
:cheers:
Just got a piccalo back in cr39 2.50 add ordered 16 high, (min suggested), at the bottom of the frame as far down as I could read it reads only 2.00D. I 'm glad I bumped it.
Try using the Piccolo template and measure through the near power verification circle (about half of the circle will be cut off if you are at 16mm high). The template keeps the much larger aperture size of the lensometer lenses from picking up the reduced power in the corridor, allowing a more accurate reading. I can assure you that my Piccolo lenses set at 19mm read the full prescribed add of +2.25, and continue to do so even when I masked the bottom 3mm of the lens.
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.
[quote]
Sometime , the O.D. & optiker have to be Jedi's Knight who will be the new hope for presbyopes. Our mission is to protect our patient from the PALs's Empire who try to sell low quality PALs in very expensive price.
You said a mouthfull!! And I am with you 100% :cheers: Chris..
Here's my evaluation of the subject. The change in minimum recommended heights is addressing the real conditions encountered by the vast majority of the population when reading a book or performing near tasks i.e reading depth, or the distance from the DVP (distance visual point) to the NVP.
F. Kozol (1996- Compensation procedures for the Anisometropic presbyope. In Perspectives in Refraction. Rubin, M.L. (Ed) Survey of Ophthalmology, 41(2) Brookline MA) discusses anisometropic presbyopes and slab-offs with segmented multifocals, but it's interesting to note that 8mm to 10mm was found to be the typical reading depth for most folks when reading. With the introduction of PALs we had to tell our clients to hold the book closer to the body and to increase the reading angle so that the NVP would better align with the reading zone of the lens, typically at 17mm to 20mm. The only problem is that it's unnatural to read at this angle, with most folks cheating by using a more comfortable reading depth of 12mm to 15mm.
The PAL designers realized this shortfall in their PALs functionality, and addressed the problem by changing to reduced corridor length designs e.g Varilux Comfort. Not a perfect solution but one that improved the physical and visual comfort while performing near tasks, primarily for the more advanced presbyopic population wearing PALs. I would take this one step further- we should be putting avid readers who are advanced presbyopes into the shortest corridor PAL possible, so that a greater proportion of the Rx'd Add resides in the area of the NVP, resulting in clearer vision and less posturing.
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.
Varilux did nothing. If you look at my post in full, which you quoted from, you will see that they did nothing. Call them and ask their techs. The definition of what "works" changed. The lens never changed. Your overall point is good, but using the evil empire as an example was poor (some later designs might reflect the change, but one already in production cannot). Definitions changed, lenses remained the same. The reason for the ever-changing fitting height of the "comfort" is that they found that giving the wearer only 85% of the prescribed power was "sufficient". The reason it changed is that it was easier to say "Get used to it" than to design something to compete with the Compact. The Empire said the Compact was bad, but people bought it anyway.
Change the data to meet the requirements- always easier than actually doing the work... it's a bit like shooting and arrow, then drawing a target around the arrow- Bull's-Eye!
"Close-Enough Optical, how may I hurt, I mean help you?"
I would like to see the contour plot of Comfort at Plano ADD 0.75D to ADD 3.50D. If I can not find , then I have to plot them by myself in Thailand.
I agree with hipoptical that Comfort is design to share the market from Compact and many wearer who get used to Compact can't switch to Comfort.
It unfair that the empire said , Compact was bad , because every PALs have bad point & good point and we still not have perfect PALs yet.
Sometime , it's just the marketing of the empire , nothing new.
" Life is too short to limit your vision"
ISOPTIK : The Hi-End Eyeglasses Centre
494 ERAWAN BANGKOK 4th floor
Ratchaprasong , Bangkok , Thailand 10330
isoptik@gmail.com
www.isoptik.com
Hotline & SMS : +66 81 538-4200
Fax. : +66 2 251-3770
:cheers:
I was referring to when Essilor introduced the Comfort about 15 years ago.
The definition of what "works" changed.
Agreed. 22mm was clearly incorrect. They have corrected their error.
The reason for the ever-changing fitting height of the "comfort" is that they found that giving the wearer only 85% of the prescribed power was "sufficient".
Sufficient or not, if the wearer has a reading depth of 12mm, then 18mm will provide a comfortable margin before you run out of lens, and that extending the lens an extra 4mm adds little functionality.
The reason it changed is that it was easier to say "Get used to it" than to design something to compete with the Compact. The Empire said the Compact was bad, but people bought it anyway.
Well, that's how empires react when they get one-upped.
Change the data to meet the requirements- always easier than actually doing the work... it's a bit like shooting and arrow, then drawing a target around the arrow- Bull's-Eye!
Yup. Marketing 101. Sure glad we're on the science end of the market!
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.
Never had a problem @ 18 ht. Increase pano tilt a little. Myopes are usually as low as 17. Hyperopes like a little extra. If possible ask the perscribeing Dr. to ok .25 extra in the add and add a little face form to increase the field.
I know a guy who never had a problem running across the freeway to avoid going down to the corner; just had to dodge a little, run, stop, run again. Never had a problem doesn't mean it's right or good. I've never had a problem putting Rx lenses into drug-store frames- doesn't mean it's the best thing to do. There are folks who post here that would say they've never had a problem fitting "Super No-Line's". You would certainly agree that that doesn't make that the best lens available... right? The empire's problem is that they simply changed the definition of "acceptable" to fit the market because they were afraid of losing market share to better lenses. The REAL problem is that a lot of "opticians" went right along with it. :finger:
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