Checking with Rotlex

[apaul]

I sent back a progressive as I couldn't get a good reading in the reading portion
As a supplier of progressive lenses I assumed they would check them using a Rotlex however they haven't one
My question is do you think it is required for a supplier to have one?
Thanks!
Alan

PS it isn't a supplier of all varifocals just their own brand

[Jacqui]

I hope Harry Chilling gets in on this one. Please !!!!!

I agree it would be nice, unfortunately it isn't going to happen. It is possible to get a close reading without one using a digital lensometer, but you need to be real sneaky. Most surfacing programs do calculate a set of corrections at the PRP that can be read using the auto lensometer.

[AWTECH]

I sent back a progressive as I couldn't get a good reading in the reading portion
As a supplier of progressive lenses I assumed they would check them using a Rotlex however they haven't one
My question is do you think it is required for a supplier to have one?
Thanks!
Alan

PS it isn't a supplier of all varifocals just their own brand

Lens mapping software can be helpful in number of ways. Just because someone has such equipment will not assure you they know how to verify with it. With any digitally cut freeform lens the possiblity for error does exist. However manufacturing mistakes with any lenes can happen at any stage for a number of reasons. Lens mapping equipment is just one helpful component.

(We do have such equipment and it does help confirm that a problem exists)

[HarryChiling]

...............

[Uncle Fester]

If they don't use any sort of mapping system it would be the equivalent of you selling glasses without a lensometer in shop.

You mean without don't you?

[DocInChina]

The sotware that comes with the Rotlex allows input of the intended design and then a snapshot of the lens post processing and will give the operator a difference map that shows the differences between the intended and the actual. It is not very difficult to read, it shows a scale ont he side fo the maps with the powers color coded. If they don't use any sort of mapping system it would be the equivalent of you selling glasses without a lensometer in shop.

From my understanding the power map cannot be converted to a point files. With a point file you could theoretically go back and re-tool the lens. What export files are available for the Rotlex and what information do they provide in the export file?

[Raanan Bavli]

As back progressive FF lenses have curvatures which do not enable measuring the way lensometers are supposed to work, an alternative method should be used.
A right way of doing this would be as follows:
1) Trust the theoretical lens design.
2) Use the point file (topography) to generate an optical power map, within the optical configuration of your specific lens mapper.
3) Map the lens
4) Subtract the measured map from the theoretical one, and compare the differences to your tolerances.

Attached is a screen-shot summarizing this chain of operations, as my customers do.

As for item #1, one should use a reputable manufacturer, as there's a limit to what one can do....

[Fezz]

As back progressive FF lenses have curvatures which do not enable measuring the way lensometers are supposed to work, an alternative method should be used.
A right way of doing this would be as follows:
[COLOR=black]1) Trust the theoretical lens design.do....[/SIZE][/LEFT]

Ah.........ok?

Why?

[Raanan Bavli]

If so, my opinion is that the design software has probably been made by top professionals and has been thoroughly debugged. Moreover, this software is tested tens of thousands of time per day by patients receiving their prescribed lenses. There's some percentage of unhappy patients but this most likely originates from other reasons (errors in prescribing, manufacturing, dispensing....). The FF production method is the weakest point in the chain. It's a great way of making lenses, but assuming that once properly setting the generator, one can make an infinite number of good lenses, is unprofessional conduct.

[Refractingoptician.com]

I thought I had one of these Rotlex units in storage in the back room . Darn , I have to get new glasses ... when I opened the box , it turned out to be old frame invoices and statements , someone had marked the box "Rotlux" .

How much do these things cost ?

[Raanan Bavli]

How much do these things cost ?

Tens of thousands of $. Beyond the reach of optometrists, and probably beyond their needs....