Mono PD VS Binocular Situation...........

[Yeap]

i have encounter a condition as this, the patient came in with a pair of glasses she has been wore it for the pass 2 years, anyway most the time she wearing contacts. her Rx OD-8.00 OS -6.50 (roughly). final prescription i did wasn't significant different but the vision with trial frame and her current glasses was significant different and i found out that the PD has been out by 3mm each. i double confirm with pupilometer as well as the Zeiss RVT. finally i corrected the PD error and she was a happy customer and she seem to adapt with it without any problem.

[obiwan]

The patients monocular PD is different for every frame they put on. Monocular PD's need to be measured for each individual frame. The total PD will of course always be the same, but the monocular measurements will vary depending on how each individual frame sits on the patients bridge.

[Barry Santini]

The patients monocular PD is different for every frame they put on. Monocular PD's need to be measured for each individual frame. The total PD will of course always be the same, but the monocular measurements will vary depending on how each individual frame sits on the patients bridge.

This is true, and is handled best by a digital-centration picture-taker.

However, its time to also ask what other variables we are *not* improving the precision of before we look at the appeal of these finer measurements as a true client benefit.

Here's a simple example: (If you don't have a tracer that allows 0.01 input of PDs and heights, you'll be outta luck here)

Input some values. Place a progressive with its engraving properly in the block. Don't move the lens.
Change the PD/height values by 0.1mm increments, and watch the movement of the protractor against the engravings.
Tell me when you reach a value difference that is equal to what you *estimate* the range of fitting variability is for any client's eyewear.

Then factor in their posture.

'Nuff said.

Barry

[conantoptics]

Most of the time, I would ue the PD's as measured and discuss expectations with pt.

Hello, this is a typical professional answer.:)
I get this answer last week too, when I was having a meeting with some old optometrists.