Custom digression in office / near variable focus lenses?

[DanLiv]

Can one specify custom digressions for NVF lenses like Shamir Auto 2 Office/Computer/Workspace? There were several digressions ("dynamic powers") to choose from in the old conventional Office that allowed me to tweak the powers for different computer viewing distances, but my labs keep telling me this isn't possible in the free forms. I am having trouble understanding why not.

First, is it the case that the free form designs of the Auto 2 Office/Computer/Workspace are fixed based on Rx and can't be altered for different viewing distance? That seems a lousy implementation of free form.

Second, if so, what tricks do any of you use to massage the Rx, design, or measurements to outsmart the lab/design and get the intermediate powers you want?

To make this concrete, I have a pt in Auto 2 Office who changed work environments and now sits about a foot further from her monitor. Full Rx is:

OD -0.25 add +2.50
OS -1.00 add +2.50

With 50% of the +2.50 at the fitting point this makes her intermediate +1.00/+0.25.

No change in Rx, but she needs -0.50 OU over current Rx and design for intermediate while maintaining the same total near power.

In the old Office I would just specify one diopter more dynamic power, which with 50% digression at the fitting point would achieve the extra -0.50. But supposedly I can't on the free forms. I talked with my doc and the trick we are thinking is to order the lens instead as the following Rx:

-1.00 add +3.00
-1.75 add +3.00

With 50% of the +3.00 at the fitting point this would make her intermediate +0.50/-0.25, exactly the -0.50 OU I need. A sacrifice is the total near power is -0.25, but doc believes she has enough accommodation left to handle that without problem. The other potential negative is that if the frame is bigger she is going to get overminused in the uppermost portion of the lens.

Anyone foresee other problems with this? Or have a better recommendation?

[IdentityOpticalLab]

Actually I'm not sure why you are being told you can't specify focal distance. there are a variety of designs, including the auto 2 office that has that as a parameter, however I believe it maxes out at a 2.25 maximum reduction, which wouldn't be an issue in this case. if they are still telling you no, you can have your lab calc it before it is made to ensure it is resulting in what you are expecting.

if you want to trick the system you can also always order a short corridor all purpose PAL with the intermediate correction at the distance with a reduced add, that seems to work well too.

[golfnut]

Or you could alter the sphere and/or add power to achieve desired results. The computer and workspace are preset but can be fudged doing it this way. At least that's what the shamir rep said?

[IdentityOpticalLab]

The workspace and computer have fixed focal distances and would need to be tricked to provide you what you want. but the Auto2 Office does allow you to specify focal distance.

http://www.shamirlens.com/index.php?...%A2&Itemid=253

[RT]

Investigate the HOYA Tact. It comes in 0.25 diopter steps (i.e. express your order as a standard progressive), and has a choice of having 40% of digression at PRP, or 60% of digression at PRP. By combining the two, you can get almost any combination of near and intermediate power that you want.

[DanLiv]

The workspace and computer have fixed focal distances and would need to be tricked to provide you what you want. but the Auto2 Office does allow you to specify focal distance.

Interesting, thanks. I have pushed with my lab and they are running the calcs now.

What benefit are the Computer and Workspace over the Office then? It sounds like each is simply a variant of the Office with different viewing distance specifications. Perhaps just simplification in ordering for less savvy opticians who don't trick out the Office?

Investigate the HOYA Tact. It comes in 0.25 diopter steps (i.e. express your order as a standard progressive), and has a choice of having 40% of digression at PRP, or 60% of digression at PRP. By combining the two, you can get almost any combination of near and intermediate power that you want.

Thanks, that sounds pretty cool. I don't do HOYA currently, but maybe I should. It seems every post anyone has looking for a great lens to solve a problem gets answered with a little of this, a little of that, but invariably a HOYA solution is always suggested.

[IdentityOpticalLab]

What benefit are the Computer and Workspace over the Office then? It sounds like each is simply a variant of the Office with different viewing distance specifications. Perhaps just simplification in ordering for less savvy opticians who don't trick out the Office?.

I think you are exactly right.

[jspayneii]

I also agree with IdentityOpticalLab, and DanLiv. The Computer and Workspace seem to be variations on the Office. I also believe this is to simplify the offering for both the lab and the ECP.

IOT did released a few new office designs in the past year giving set focal distances. The lens designers do not always do a good job explaining, or even tell us that these parameters are configurable. Up until today, I was unaware that the Autograph Office was adjustable in this manner. I will be calling Shamir about this on Monday.

The other thing that I find odd is that the Computer and Workspace are available in more materials than the original Autograph Office lens.

[eyec123]

With shamir office powers are fixed but with autograpgh 2 office you can tell the lab how far away the screen is and they can make it for that distance.If you tell them 46 inches away they can chage the dynamic power for that distance. I have never had the situation to do that but that is what my lab tells me I can do.

[Robert Martellaro]

When we design task eyeglasses for desktop monitors, we need to know 1.) distance to the screen 2.) distance to the desktop/copy 3.) vertical height and placement of the screen 4.) the work distance of the prescribed add power from the refraction Rx.

Set the reading card at the work distance and refract. This value becomes the distance power for the multifocal lens. Refract for the secondary work distance, typically the desktop. Use a multifocal design that has a generous distance zone, and position the fitting height to avoid posturing (at or slightly below center screen, and at or below the bottommost part of the screen if segmented.

Why is this superior to proprietary PAL designs?

The corridor length is only as long as necessary, does not extend above the primary gaze, does not limit horizontal field of clear vision or require posturing. Note the corridor and degression of the Shamir Office and Auto 2 Office (and other brands)- it extends about 10mm above the primary gaze to 20mm below, with about the narrowest field of vision right at or slightly below the primary gaze, exactly where you want widest field of vision!

http://www.shamirlens.com/index.php?...711&Itemid=253

Look at the vertical view angles of the Office.

http://www.shamirlens.com/index.php?...ce™&Itemid=253

Maybe a good lens for someone who sits at a desk, greet clients, and uses a small 11" or 13" laptop.

The Shamir Computer looks better, but they still insist on giving clean vision out to 5'. It's not clear if you need to lower your chin to clear this distance. If you do, likely I think, then the progression extends above the primary gaze, limiting the horizontal fields somewhat.

http://www.shamirlens.com/index.php?...ace&Itemid=253

Regardless, a radiologist, accountant, or any heavy user of single or multiple desktop monitors needs wide and tall fields of clear vision at their work distance and height. Don't compromise just to save them a few bucks, give them what they need. It may even be an matter of life and death!

[merrymaker]

Anyone have feedback on the new Unity CVxpression NVF lens? It is nice to have a new FF occupational available in 1.67 and with idiot-proof distance selections.