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?
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