0. Most people are symmetrical, or darned close to it. In your case, the
asymmetry is a little more pronounced. Mine are only about 0.5mm off.
The two numbers represent the measurement from the center to your left
pupil, and the center to your right pupil. You add them for your PD
distance.
1. Most of the retailers I'm familiar with have a "special notes" field at
the end of the ordering process. You just type in any special instructions,
like your monocular PD measurements, in that field. This is where I always
put my monocular PD measurements, even when ordering from Zenni. My results
have been nothing short of perfect, every time.
As to its importance... PD is important, but it becomes much more critical
at higher prescription strengths. What is your prescription?
2. Even as critical as it is, 1/2mm variation is not going to be
significant. Flinching, moving, and daily variations in fluid pressures can
cause measurement errors greater than that. Round it in either direction.
Precision is important, but there's no reason to bring out the OCD.
-- Chuck Knight
P.S. I'm guessing you're either an engineer or a programmer. You started
counting at zero... :-)
On Sun, Feb 15, 2009 at 12:38 AM, 703 Crew <tomm...@gmail.com> wrote:
>
> Hello there -
>
> First time internet glasses shopper here, and it was hell getting my
> PD measurement. I finally got them and some binocular thing was used
> and it gave me:
>
> 29.0 R and 27.5 L
>
> I have found that a lot of internet retailers just ask for the sum of
> both numbers, but is there anywhere where I can get my right lens
> calibrated for 29.0mm and 27.5mm for the left eye? I am guessing if I
> submit a request for PD of 56.5 they are assuming a symmetrical split
> of 28.25mm/28.25mm which is not the case...
>
> 0. If PD is just a measurement from pupil to pupil, why did the
> binoculars give me two different numbers?
> 1. Does this matter? Should I pursue somewhere that will do PD per
> eye (since mine is not even) or is it okay to sum it up?
> 1b. Does anyone know internet retailers that do PD per eye?
> 2. If my number is 56.5, should I round up or down?
>
> Thanks in advance,
> T
>
> >
>
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