I have a few questions about parametric measurements for GT2 (and progressives in general):
1. Should DV mono PD's be used, or should Mono NV PD's be used? If Mono NV PD's, should the dispenser keep the specific inset used by Zeiss for a set of GT2s, and center the NV to match the actual insetted-NV, or just go with the DV PD's. I've found that essilor-pupilometer-derived mono NV PD measurements are often not *symetrical*(by this i mean that the NV PD's are not equal to the DV PD's, less 2.5mm each) with the actual DV taken. Please note that I do take the measurements a few times to confirm their repeatibility.
2. Is the layout "Comp" (*my* word for the mm distance between the fitting cross and the MRP) still 6mm for a Zeiss progressive? (and why is it 6mm anyway??? I think Zeiss should consider moving to the more common 4mm, just to eliminate fabrication and checkout errors when using "circles" as reference point during edging and subsequent verifications)
3. What are the *default* values Zeiss assigns for POW (position-of-wear: phoropter/focimeter parameter compensation; VD, PANTO, FACE FORM, nearpoint vergence) for GT2?
4. Is GT2's rear surface "free-form"? (not evident from the white paper)
Thanks in advance for your responses. BTW, I'm not trying to ask anything that is *proprietary*
Barry Santini, ABOM
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