Thickness Problem with Physio 360 1.74

**xiaowei** · 11-01-2008, 07:38 AM

Originally Posted by JanMueller

If there are high plus powers combined with high additions, then the guys making the lens have to use higher base curve to get the same reading power like a conventional front surface design.
So it has to get thicker...

Sorry to interrupt, but IMHO this is the original claim only put in different words. WHY would this be necessary compared to a non FF design? Why doesn´t it apply for a conventional design, too?

And also, in a "true, full" FF design, there would no longer be any "base curves" in the traditional sense, i.e. no fixed limited choice.

Also "conventional wisdom" (i.e. advertising;)) usually claims that aspheric designs (where you could use more degrees of freedom just in a FF design),
will lead to "thinner" lenses (in the sense of less bending) for the same amount of off-axis gazing. I know this might collide with PAL "design rules", but a good compromise here is just what makes a successful PAL.

Sincerely

XW

**JanMueller** · 11-01-2008, 12:59 PM

Just order two lenses which have the same diameter, power and material and you will see it's thicker.
I have done it and it was obvious.
I got the information from an article of an german lens manufacturer who wrote this in the most important german journal of opticians.
He was the first one who told us the truth although he has his own FreeForm in stock.
If somebody spits into a mould, makes it warm and tells you that what comes out is a FreeForm then this must not be better then a conventional design.

**Bob MacNeil** · 11-01-2008, 11:01 PM

Good frame selection, aspherics are more important then index selection for high plus Rx work, lab may be having problems with lens diameter knifing out on surfacing chuck ask for 0.5m/m edge at frame 180 temple side.

**KStraker** · 11-12-2008, 11:46 AM

Originally Posted by sharpstick777

But our local rep and Hoya lab kind-a suck.

I just received a 1.67 Id lifestyle from Hoya. Rx is:
+6.75-1.25X150
+7.00-1.50X10
+2.25 ADD
The thinnest edge is just inside the rim of the frame(full metal). I refuse to believe that a $500,000 generator is limited by a $5.00 block(as some have suggested). Standard or freeform, spherical or aspheric, it's a chunk of plastic and you should be able to control the parameters of the finished lens. If your lab can't do a good enough job, order a lifestyle id from Hoya Atlanta.

**LENNY** · 11-13-2008, 11:19 PM

Originally Posted by RT

More likely, what is happening is that the lab is running into limitations with their blocking system. Since FreeForm processes do not typically use wax blocking, the generator is unable to cut into the blocking material (or else it would ruin the lathe). On a high plus lens going into a smallish frame, therefore, the lens has to come out thicker to keep the lathe from hitting the block. When the lens is then edged out of the resulting surfaced lens, the edge thickness is thicker than desired. It all depends upon the diameter of the blocks available to the FreeForm process. I have no idea if smaller diameter blocks can be used in that particular lab's process.

So there was no 1.0 edges on the smaller lenses when alloy is used?

**jjbons** · 11-14-2008, 09:21 AM

Originally Posted by sharpstick777

But our local rep and Hoya lab kind-a suck.

If you don't like your local HOYA lab, HOYA has over 110 independant distribution options. They can't all suck.

**gemstone** · 11-14-2008, 04:17 PM

Thickness is pretty basic for quality. If they can't get the thickness correct, how do you think the rest of the quality is going to be? Go with a Sola or Hoya product.

**Floyd** · 11-14-2008, 07:28 PM

Edge thickness should be 1.0(or less) on high plus lenses. I've had no issue getting 1.74 360's at correct edge thickness. I think Plus lenses are a little tricky to guess what you should use but at that high of a power 1.74 would be my choice.
As far as Uncuts go on previous post, I agree. Even with A,B and ED measurements, a traced frame seems to always work better.

RT · 11-15-2008, 11:13 PM

I just received a 1.67 Id lifestyle from Hoya. Rx is:
+6.75-1.25X150
+7.00-1.50X10
+2.25 ADD

Although Hoya appreciates the positive mention, the key thing about the original post is that the plus lens is going into A VERY SMALL FRAME. The power alone is not what is causing the problem...it is the combination of the high plus and the small frame. Any lab using a blocking method that does not allow the generator tool to cut into the blocking material will have a problem with that combination--and it doesn't matter if it is a FreeForm progressive or a conventional progressive. It would be unfair to suggest that one or two lens manufacturers somehow have a monopoly on correctly calculating thickness on plus lenses.

Fortunately, several companies showed new blocking systems at last week's OLA convention that could relieve the problem.

I refuse to believe that a $500,000 generator is limited by a $5.00 block

I could give you a long list of things that I refuse to believe about opticianry, but yikes--I'm afraid those are true too. And it's not the $5.00 block, it's the incredibly expensive diamond cutting tool that is being protected.

So there was no 1.0 edges on the smaller lenses when alloy is used?

It depends upon the size of the frame, how high the Rx is, and the actual process used (blocking method etc.). Unfortunately, there's no hard and fast rule.

**KStraker** · 11-17-2008, 10:34 AM

Originally Posted by RT

Although Hoya appreciates the positive mention, the key thing about the original post is that the plus lens is going into A VERY SMALL FRAME. The power alone is not what is causing the problem...it is the combination of the high plus and the small frame. Any lab using a blocking method that does not allow the generator tool to cut into the blocking material will have a problem with that combination--and it doesn't matter if it is a FreeForm progressive or a conventional progressive. It would be unfair to suggest that one or two lens manufacturers somehow have a monopoly on correctly calculating thickness on plus lenses.

Fortunately, several companies showed new blocking systems at last week's OLA convention that could relieve the problem.

I could give you a long list of things that I refuse to believe about opticianry, but yikes--I'm afraid those are true too. And it's not the $5.00 block, it's the incredibly expensive diamond cutting tool that is being protected.

It depends upon the size of the frame, how high the Rx is, and the actual process used (blocking method etc.). Unfortunately, there's no hard and fast rule.

We have a surfacing lab, so I'm familiar with those issues. My rx calculator somes up with a minimum blank size of 60mm. My smallest block is 55mm wide. How big are the blocks for a free form generator? Why don't they make a small one to accomodate this kind of work?

Oops, on a reread, looks like someone is addressing this issue.

**sharpstick777** · 11-17-2008, 08:52 PM

Out of RX range for an ID Lifestyle...

Hoya ID would work but its not a VSP lens.

Originally Posted by jjbons

If you don't like your local HOYA lab, HOYA has over 110 independant distribution options. They can't all suck.

You're right but I don't want to open another account with another lab.

Sharpstick

**KStraker** · 11-18-2008, 08:33 AM

Originally Posted by sharpstick777

Out of RX range for an ID Lifestyle...

Hoya ID would work but its not a VSP lens.

You're right but I don't want to open another account with another lab.

Sharpstick

The free form stuff will be forwarded to a particular facility. It will not be done by your local Hoya lab.

**ezrich** · 11-20-2008, 02:55 PM

sharpstick777 essilor dallas is bad news. we quit doing ipseo's, switched to autograph's. try digital eye lab 1 866 866 8673 in ny.

**sharpstick777** · 11-20-2008, 04:17 PM

Originally Posted by ezrich

sharpstick777 essilor dallas is bad news. we quit doing ipseo's, switched to autograph's. try digital eye lab 1 866 866 8673 in ny.

I have noticed and increase in remakes, and decrease in turn around time, and overall drop in the lenses we get from Dallas (just barely within tolerance instead of dead on).

Anyone from Essilor care to comment on these issues? Pete have you seen this thread?

Update: The job is in Dallas as we speak, they say they are sending lenses with satisfactory thickness ( I believe we are on remake number 8)? They tell me the problem is a software issue, not an equipment issue. My lab has given me Physio 1.67's as loaner lenses since we are now 6 or 7 weeks into this. I do want him into an Atoric design with his RX though.

Sharpstick...
and getting sharper...

**gemstone** · 11-20-2008, 10:52 PM

Really? Do you think that the #1 priority for the big E is getting proper thickness on one lens on one order?!! Really?!! Who do you think you are?

**sharpstick777** · 11-20-2008, 11:17 PM

Originally Posted by gemstone

Really? Do you think that the #1 priority for the big E is getting proper thickness on one lens on one order?!! Really?!! Who do you think you are?

Um, how did I get flamed in this? I never said I was anything or anyone special. Essilor tells me they are still trying to work on the issue, all I did was update the thread.

I think I am an Optician who asked for a lens in a certain perscription that was within the manufacturers stated parameters. Where do you read into this that I am anything more?

Sharpstick...

**gemstone** · 11-21-2008, 07:13 AM

Originally Posted by sharpstick777

Um, how did I get flamed in this? I never said I was anything or anyone special. Essilor tells me they are still trying to work on the issue, all I did was update the thread.

I think I am an Optician who asked for a lens in a certain perscription that was within the manufacturers stated parameters. Where do you read into this that I am anything more?

Sharpstick...

Sorry. You could not see my toung in my cheek when I was typing that. Please don't take me too seriously.

**sharpstick777** · 11-21-2008, 03:41 PM

Originally Posted by gemstone

Sorry. You could not see my toung in my cheek when I was typing that. Please don't take me too seriously.

Its all good Gemstone...

Physio 360's arrived today in great shape. Rx was dead on, min edge thickness was 1.0mm and 1.6mm. The lab did them gratis for the delay.

Although I really appreciate Essilor going to work for this one patient and willing to chew through a ton of lenses to get it right, I wonder why they didnt catch this potential issue when they were doing testing? Its my understanding that before a paramater becomes official they test it first.

When Definity launched I think you could only order it up to a -2.00 because testing had not been done on higher powers.

Unlike some I actually have been impressed with Essilor on a few occaisions, and I appreciate the work they did to get this job right. But I would love to hear from an Essilor suit to why testing didn't catch this.

Sharpstick

**HarryChiling** · 11-25-2008, 06:55 PM

Can anyone here imagine what a knife edge on a lens would do to a conformable lap? Chances are even if they got it to the 1.0 or less edge thickness the lap would be destroyed and you might get a lens that had issues polishing out. Just another potential issue I could see causing some of the issues.