4.50 Add?

**misstara007** · 06-25-2009, 04:34 PM

I just recieved an Rx with add power of 4.50... OD wants her in a PAL. What to do?

**HarryChiling** · 06-25-2009, 04:36 PM

Originally Posted by misstara007

I just recieved an Rx with add power of 4.50... OD wants her in a PAL. What to do?

Tell them you can't get that lens and count your blessings. Or send them back to the doctors office for them to fabricate them.

**Fezz** · 06-25-2009, 04:37 PM

Originally Posted by HarryChiling

Or send them back to the doctors office for them to fabricate them.

:cheers::cheers::cheers:

**Fezz** · 06-25-2009, 04:40 PM

This thread may help:

http://www.optiboard.com/forums/showthread.php?t=34455

**Uncle Fester** · 06-25-2009, 05:23 PM

So how did that +3.75 potential progressive work out?

Sorry for the skepticism but didn't we just go through this?

Check out the pictures of add powers and intermediate limitations from this course on progressives by Dayrl Meister.

http://www.opticampus.com/cecourse.p...essive_lenses/

Show this to the OD if need be!:)

**Uncle Fester** · 06-25-2009, 05:50 PM

See if I can make these pictures appear-

Because of the first two points, the size of the progressive corridor will depend upon both the length of the corridor and the Add power. This means that lenses with shorter corridor lengths or higher Add powers will by necessity provide less intermediate vision and mid-range utility.

**jameselex** · 06-25-2009, 06:32 PM

Originally Posted by misstara007

I just recieved an Rx with add power of 4.50... OD wants her in a PAL. What to do?

or if you can find someone brave enough to free form a backside pal 2.5 add on a conventional 2.0 add blank. There might be some misalignment but it's better than nothing. Too bad my freeform generator is still on my wish list.

**misstara007** · 06-25-2009, 06:48 PM

That other one I was asking about with the high add worked out the last time I checked with her which was a couple of weeks after dispense...

I knew that's what you guys would say... (FT is the way to go) I know I know.... this Rx was written at MY practice, so I have to fill it. The pt. has worn PAL for YEARS and last rx had a +4.00 add... My lab is going to try and get me a free form lens (Succeed or Autograph) Yet to hear from them if they even CAN.

We'll see....

**chip anderson** · 06-25-2009, 07:08 PM

Have you concidered sitting down with the doctor and explaining the error of his ways?

**DragonLensmanWV** · 06-25-2009, 07:14 PM

Originally Posted by misstara007

That other one I was asking about with the high add worked out the last time I checked with her which was a couple of weeks after dispense...

I knew that's what you guys would say... (FT is the way to go) I know I know.... this Rx was written at MY practice, so I have to fill it. The pt. has worn PAL for YEARS and last rx had a +4.00 add... My lab is going to try and get me a free form lens (Succeed or Autograph) Yet to hear from them if they even CAN.

We'll see....

Your docs need to take some lessons on what lenses are functional or even made. Ask them which progressive they prescribe for that particular RX. At the focal length of that 4.50 their eyes are going to be converging more than what the progressive is tooled for, so they'll not have any intermediate at all. Have you considered the TRO blended backside lens? You won't have any intermediate either way, but you can get the TRO in any material, and it's as invisible as a progressive.

**Uncle Fester** · 06-26-2009, 08:13 AM

Originally Posted by misstara007

That other one I was asking about with the high add worked out the last time I checked with her which was a couple of weeks after dispense...

Ryser's Rule of progressive's works!:D

**Uncle Fester** · 06-26-2009, 10:49 AM

Originally Posted by DragonLensmanWV

Your docs need to take some lessons on what lenses are functional or even made. Ask them which progressive they prescribe for that particular RX. At the focal length of that 4.50 their eyes are going to be converging more than what the progressive is tooled for, so they'll not have any intermediate at all. Have you considered the TRO blended backside lens? You won't have any intermediate either way, but you can get the TRO in any material, and it's as invisible as a progressive.

Great advice and suggestion!:cheers:

**braheem24** · 06-26-2009, 11:04 AM

Originally Posted by misstara007

I just recieved an Rx with add power of 4.50... OD wants her in a PAL. What to do?

Explain the situation to the patient and make it in a D-35 or 2 pairs 1 SVD and 1 SVN.

At a +4.50 add, patient barely uses the bifocals already, unless reading while touching her nose which brongs up another subject (BI prism).

The OD's suggestion is just that, it's up to you as a good optician to explain the options and consult with the prescribing doctor if necessary.

**Chris Ryser** · 06-26-2009, 12:20 PM

Originally Posted by Uncle Fester

Ryser's Rule of progressive's works!:D

Thanks Fester...........

A progressive lens with an add of 4.50, if you could even get it, would be a guaranteed object to refund all the money you took of the patient, and he would badmouth you all around town that you wanted him to be dizzy for the rest of his life with 2 miles of distortion in front of his eyes.

Never tried before: Give him a lens with a 1.00 addition, has only 1/2 mile of distortion and put a stick on bifocal with an add of 3.50 on the minus side. Could look a little different but might even work.

...

.................:D...................

...

**HarryChiling** · 06-26-2009, 12:39 PM

Chris, Jameselex had a great suggestion on using a back side progressive surfaced onto a front side progressive although additively your still in the same boat with the amount of garbage in the lens. His idea is sound though and could be done with a blended round seg on the back of a low add progressive, this could provide a similar lens to the At Last without the line, and have less garbage than an all PAL choice. It's gonna be nice when labs eventually open up to alternative designs. I have been saying it for years and I have been focusing my energy on design and math for that day.

**Robert Martellaro** · 06-26-2009, 01:15 PM

Originally Posted by DragonLensmanWV

At the focal length of that 4.50 their eyes are going to be converging more than what the progressive is tooled for...

Right. That's about 22cm which works out to a about a 3.5mm inset- more if the distance PD is very wide and/or if the distance power is plus.

Originally Posted by misstara007

I just recieved an Rx with add power of 4.50... OD wants her in a PAL. What to do?

+4.50 PAL? None that I'm aware of. However, one might bump the distance +.50 and use a +4.00 Add PAL, with the doctor's approval of course.

Originally Posted by misstara007

... My lab is going to try and get me a free form lens (Succeed or Autograph) ...

Might be a problem getting that much power on the back, especially if the distance is plus, if they can do it at all, with or without the proper inset. If they can give you the power but not the inset, consider increasing the distance decentration to compensate. I suspect the German opticians would have a better shot at this, probably with the Gradal Individual, which has the free-form surface on the front along with the progressive optics. The inset is also customizable from zero to who knows how far in. Odds are you'll have to fit an auxiliary pair of readers or segmented multifocals.

**hipoptical** · 06-30-2009, 08:46 AM

I think the best solution for you is to find someone to cut a 3.50 freeform on the back of a 1.00 add traditional PAL. I know someone who would do it just to see if it would work. PM me your contact info if you're interested and I'll have him call you.

**NgCognito** · 07-08-2009, 12:02 PM

go to www.thelensguru.com He/she will lead you to +4.00 adds. There are none listed any higher.

**MarcE** · 07-08-2009, 10:37 PM

Originally Posted by DragonLensmanWV

At the focal length of that 4.50 their eyes are going to be converging more than what the progressive is tooled for, so they'll not have any intermediate at all. Have you considered the TRO blended backside lens? You won't have any intermediate either way, but you can get the TRO in any material, and it's as invisible as a progressive.

BINGO! Dragon is correct again. This is the real issue:

The patient couldn't use a 4.50 add if it were available because it won't be at the correct inset. Even at a +3.50 add there isn't any intermediate available, so might as well use a blended.

The TRO seg actually is a "no-line", although it isn't a progressive. With AR, it almost completely disappears. But on a +4.50, you might be able to see the blur.

I did it on a +2.75 add first time "no-line" wearer that was voted an "instant redo" by everyone in the office - including the prescribing Dr.
I used the TRO seg w/ AR and Patient, Dr, and I was happy. The only sad ones were the ones that lost the bet.

**hipoptical** · 07-09-2009, 08:46 AM

Some digital PALs have a variable inset, so if you start with a low add standard PAL (.75 or 1.00), and digitally produce the majority with a customised lens, it is likely to work. I would be willing to try just to see if it could be done. Someone send me an order, and I'll have it done through my friends. Then we'll have something other than theory to discuss.

**chip anderson** · 07-09-2009, 01:50 PM

Just tell the doctor you think it ain't gonna work, and ask if he's willing to pay for it if it doesn't.

Chip

**hipoptical** · 07-09-2009, 03:00 PM

Originally Posted by chip anderson

Just tell the doctor you think it ain't gonna work, and ask if he's willing to pay for it if it doesn't.

Chip

Pay for what? Send it to me and I'll get it done n/c just for kicks and grins- you know, just to see if it can be done. If it doesn't work, then you know the theory you use is correct, if it does work, then we have a possible "game-changer". (In which case the folks that made it would appreciate some kudos, I'm sure.) I stand to gain nothing in this, I just like to try impossible things and I have friends who help me to do so. (For all I know the calc software may reject it from the start- at least supply an Rx so we can try it...)

**chip anderson** · 07-09-2009, 04:35 PM

Gettin it done is no problem. Getting the patient to see well out of it it the part that won't work.

There is no need to sell optical junk for a higher fee or better cosmetics if the optics suffer.

Chip

Even if it does "work" if the patient were given another type of bifocal to compare, he would say: "Duh, now I can really see."

**majucalicut** · 07-10-2009, 01:11 AM

In pals you will get the addition between +0.75 and +3.50. So +4.50 is not available

**hipoptical** · 07-10-2009, 09:49 AM

Originally Posted by chip anderson

Gettin it done is no problem. Getting the patient to see well out of it it the part that won't work.

There is no need to sell optical junk for a higher fee or better cosmetics if the optics suffer.

Chip

Even if it does "work" if the patient were given another type of bifocal to compare, he would say: "Duh, now I can really see."

In THEORY the patient will not see well. I agree that this is likely the case. There was a time in our not-so-distant past that science played a part in "theory". (Meaning that a hypothesis was drawn, tests were run on or against that hypothesis, and results were discussed and verified to produce a working theory.) Theory is great as long as the stus quo doesn't change. When things change, a new hypothesis needs to be drawn up, and it needs to be tested to see whether the old theory works in all cases, or a new theory is proven for different circumstances.
In this case, customised lenses COULD be a game changer- and you'll never know as long as you sit in the stands talking about the "good 'ole days". What's the harm in testing your theory- it's PROBABLY still valid, but it may not be. Are you afraid of being wrong? Or just stubborn? I believe that anyone who is truly sure of something is not afraid to have that thing tested.
I sometimes allow my kids (and my employess) to do things I know they shouldn't do (nothing bad or dangerous, mind you) just to show them that I know what I am talking about.