New Member, Need Help on DBL

[UnknownOptician]

Hello, everyone I have been an optician for over 10 years, and I am having the most difficult time to the point where I need to ask some of you on here. I hate not knowing the why behind things, so I apologize if this question is basic or whatever. But, I have a DVX frame that states that the DBL is a 13mm imprinted on it. The lab that did the lenses made them saying the DBL was a 12.44, our tracer will tell me that it is a 12.9 and so on and so on, all around the 12-13 range. Now, my confusion is coming from me actually measuring the DBL, looking at it, Im getting a 16-17 range. Which, as you can imagine, is throwing my patient completely off. Can someone PLEASE explain, what is going on with this frame? The model is the DVX Next... I want to make her PD smaller now, to compensate for this 4(ish)mm difference, but if there is something that I am not seeing when measuring this DBL, that would be good to know as well... Unless it's me not compensating for the bevel for it being a safety frame... Idk.... Thanks guys, hope everyone is doing good and pleasure to meet everyone.

[Lensman11]

There is only one way to measure a dbl I think I know what you doing wrong. The dbl is the closest distance between the eyewires The tracer knows this when it gives a measurement. I think you measuring at the middle of the eyewire that why you are getting a larger measurement. If the finished pd is wrong it is not due to dbl issue but decentering incorrectly

[PRECISIONLAB]

Lab should be taking a manual measure of frame PD along the datum line of the frame and adjust before blocking lenses. The 3-4 mm difference from trace vs ruler is due to wrap of the frame and eventual adjustments of lens size (usually larger) when edging.

Lab should be verifying PD and redo if not correct.

[UnknownOptician]

Thank you both for your replies. Both actually cleared the fog I was experiencing. Helped a ton and now know what to do for the resubmission. Cheers!