:angry: I'm really ticked at my lab. they are telling me they can't make a poly polarized progressive less than 2.2 because of the placement of the polarized film. I say that is BS. Anyone know how far back the polarized film is. This is enough to make me switch labs.
Wrong lab. Yopu should be bable to get 1.5 with no problem. I would not go thinner than that. (depends on the rx though) What is the Complete RX?Originally Posted by k12311997
OD -7.75 -.50 005
OS -6.25 -.50 180
Add +2.00
Film placement depends on the manufacturer. With some, you can go down close to 1.0 center on minus. Call your lab back and ask for someone who actually knows something about lenses. (If you were just talking to customer service, then give them another chance- that's what I would want.) It may be that they can't do it because they will only use one supplier; ask for another brand. If they still refuse, then tell them someone on Optiboard knows a REALLY GOOD lab in Texas that will be happy to help you. :bbg:
I'm trying to recall a CE class from KB Co a few years ago. The presenter as I recall was bragging that they had a casting process that placed the film 1.1mm from the front of the lens which was closer than anyone else. I think you are limited to Nupolar products however.
Found the Nupolar FAQ from the CE! "Image can be safely ground to 1.8 on all base curves". I think you are SOL on other types of progressives.
Younger technical hotline (at least a few years ago) 1-888-807-4950.
On second thought I should have left this to the lab people! You guys are quick!!
Last edited by Uncle Fester; 06-26-2007 at 02:29 PM. Reason: on second thought
My understanding is that the film in most polarized lenses is between .5mm and 1.1mm from the front surface. Younger's lenses are .7mm (Drivewear). Younger does suggest that the minimum lens thickness "target" is 2.2mm.
Last edited by Fezz; 06-26-2007 at 02:46 PM.
This is slightly disturbing. The original poster doesn't happen to know the minimum thickness, but is convinced that the lab is a bunch of morons. The fact that they answered the question notwithstanding.
As has been mentioned, different lens manufacturers use different polarized processes, which result in different surfacing requirements. And different base curves have different laminate thicknesses--in many cases, the flatter bases have thicker laminates. Given the Rx you're looking for, that could be the case. Laminate thickness on poly polarized progressive can run anywhere from 1.0 mm to 1.8 mm. You'd want to surface the lens a little thicker than that to be safe.
It's possible that the person on the phone at the lab was mistaken. 2.2 mm sounds awfully conservative. But you really should learn the details of the thickness requirements before specifying a particular brand of lens, and before assuming once again that all lab personnel are morons.
RT
KBco., lists the film as little as .3 away from front of lens for the Wrap Solutions Series. www.kbco.net
BUT.....Keep in mind, that some labs have policies on lens thickness. Whether you can or can not grind thinner may be a mute point. Call back and speak to someone else.
If you can find where I said all or for that matter any lab personnel are morons I would mail you a crisp twenty. Now as for lens manufactuers who assume opticians are morons, they need to get a grip.
If it is the case of brand then the lab should have notified me prior to processing and recommended an alternate as I had specified 1.5ct. If it couldn't be done the lab should have notified me prior to processing as I had specified 1.5ct.
I worked in the lab at LC and yes we used KbCo so if as fester stated above they are closest to the front that would explain why we never had a problem surfacing to 1.3 to 1.5.
I'm speaking with the lab manager if he says it can't be done they wouldn't do it if they could.
I just wanted to see what you guys thought, what your experiences are, and if anyone knows the depth of placement of the films.
I checked the specs on Kbco.net the farthest imbeded is 1.3 and the recommended thickness with that is 1.8.
I'm sure it will vary with manufacturer but I could have just saved me andthe pt money and just ordered plastic at 2.2
You should be able to safely grind that to a 1.5.
Who cares how far the polarized film is from the front of the lens. Its how far the back of it is from the front of the lens or the back of the lens.
If the polarized film is 1mm thick and 1mm from the front of the lens this means that at 2mm thickness you will be cutting into the polarized film. Even with more the lens (back lens) will not be very strong.
Chip
A very valid point which brings up another variable to be mix, but still dosen't answer the qustion of how thin can they be made safely.
from kbco FAQS
How thin can these polarized lenses be surfaced?
The following are our recommended center thickness': (a) normal cr-39tm polarized lenses - 1.8mm (b) hi index polarized lenses - 1.7mm (c) polarized polycarbonate lenses - 1.5mm (d) glass polarized lenses - 3.0mm to 3.5mm. Our glass lenses require additional center thickness to accommodate the front wafer and segment thickness.
If my customers requested a polarized thinner than recommended, I'd would explain why not. If they still insisted, I'd ask them would they wouldn't mind paying for a lens with a white circle in the middle. Also I would say we cut through lenses when leaving thicker than the manufacturer's recommended. KBCO would give no argument about replacing these lenses.
I called the lens manufacturer and was told 1.7 was their min recommended. Called the lab was told (before relating that I called the manufacturer) that the computer has the information from the manufactures as to minimum thickness that could not be overridden and was given two alternative progressive design choices that could be cut thinner. After telling about my conversation with the manufacturer he told me would look into it and call me with what he found out. a week later and no call back I recieved a new pair of lenses 1.8ct.
I shouldn't have to work that hard to give my patient the best looking glasses.
Hopefully, everyone that wrote in and said "You SHOULD be able to grind that to 1.3 or 1.5 mm" pays attention to the fact that this manufacturer recommends 1.7 mm for this particular progressive. As was noted by several posters, the minimum thickness can and does vary from mfr to mfr, and from progressive design to progressive design.
So in this case, there were 2 problems. The original order was for 1.5 mm, which is below the mfr's stated specs. And the lab had a blanket 2.2. mm setting, which was also inappropriate.
I agree that the lens mfr's should probably do a better job, particularly on progressives, of advertising the minimum thickness to prevent the bad feelings between the lab and the ECP.
RT
Why blame the mfg? Quite possibly they did tell the Lab and they just didn't pay attention. None of us can keep up with all the written material and work too. Few of us have an employee who can donate all his time to reading all the written material.
There are now so many progressive designs on the market that I doubt that any of us know all of them. Same with polarized lenses albeit a lesser amount on the market.
Does anyone know all the contact lenses on the market and thier specifications?
Anyone even know all the lens tints and what coatings they are or are not compatable with? Do we even know all the types and sizes of optical screws?
I suspect that any manufacturer will be happy to tell you almost anything about any lens the make except "propriatory designs" but I also doubt that they will tell you if you don't ask. And there are so many on the market that we don't even know all the things to ask.
everyone's answer was valid within their own experience especially those using KbCo product as per their FAQ.
One of the two options provided to me by the lab for a thinner lens than the 2.2 was 1.5 the other 1.7 and I believe having found one flaw in their database others could be expected so I still doubt the worth of their knowledge. I chose to stay with the lens design over the thickness issue for .2mm.
The real problem was
1. the time the lab wasted because they made the first pair without notifiying me first of that my request was not possible
2. then not offering a solution untill the third phone call
ps. for those of you keeping score I still haven't called anyone a moron.
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