I'chiliad not an eyecare professional person, so I hope it's OK that I post here. I saw some posts past people who weren't eyecare professionals, but those were from some time ago, and I noticed when registering that yous inquire that only eyecare professionals register. But on the other hand, y'all take a subforum intended for professionals only, so I thought elsewhere in the forum might be OK for non-professionals.

I accept a question, as a patient, about pupillary distance for intermediate glasses (myopia, presbyopia).

My optometrist doesn't record PD, and my last optician visit was long ago and they no longer have me on file. I'grand ordering glasses online while quarantining, so am avoiding going in person to measure PD. I measured Dist PD myself using this method and found information technology to be 64mm.

My question is: should I adjust Dist PD for these intermediate spectacles?

I read ane source that says Dist PD is used for both distance and intermediate and Near PD is used for near. Conversely, the online store I'm ordering from brash me they use Near PD for intermediate.

I know at that place's a formula (and tables, as well equally a dominion of thumb where you subtract 3mm from Dist PD) to calculate PD for a given working distance, from a measured Dist PD ("Arrangement for Ophthalmic Dispensing" 3rd Ed. p.32, image from Amazon preview):
Click image for larger version.  Name: CROPPED - FireShot Capture 4159 - System for Ophthalmic Dispensing_ 9780750674805_ Medicine & He.jpg  Views: 7  Size: 25.9 KB  ID: 14703
I found that the Optiboard members, drk and HarryChiling, expressed it in this form:
Nigh PD = [Altitude PD mm * (10 * Reading Distance cm)] / [(10 * Reading Altitude cm) + 27]
or
NPD / WD = DPD / (WD + CTR)

I sit between 19" and 32" from the screen, normally between 24" and 32", and less often at 19". My optometrist kindly provided new adjusted prescriptions (without PD) for nineteen" and 32" working distances (using my existing unadjusted prescription on file with ADD power):

Lawmaking:

              Sphere  Cylinder  Axis OD -v.l   -0.l     125 OS -four.75   -0.75     055 Notes: computer dist nineteen inches abroad

Code:

              Sphere  Cylinder  Axis OD -six.00   -0.50     125 OS -v.25   -0.75     055 Notes: computer dist at 36 inches abroad
Using the formula in a higher place for PD, I plant my PD for 19" WD would be 60.6 mm, PD for 24" WD would exist 61.3mm, PD for 32" WD would be 62.0mm (with Dist PD = 64mm).

I'll probably employ, and submit to the shop, the SPH and prescription for nineteen" WD.

Simply should I submit one of those PD's adapted for intermediate working distances, or should I avoid adjusting the PD and submit a PD closer to the Dist PD, for versatility's sake?

Although the SPH of the glasses volition be optimized probably for a WD of 19", I'm hoping to use the spectacles for multiple distances around the business firm during quarantine: perfect intermediate vision, OK nearly vision, OK (imperfect) distance vision (just around the house, no driving). I have a 35-year-old pair of broken single-vision distance glasses which does all those things surprisingly well, while using Dist PD equally its PD. So I wonder if it's possible to indistinguishable this with the new glasses, and if i of the ways to exercise and then is to set Dist PD as the PD.

The 35-twelvemonth-old glasses seem similar to what the new intermediate glasses would exist (single-vision altitude glasses with not-strong-enough altitude prescription) and also are similar in the style I'd use them (for multiple distances effectually the house).

I consider my presbyopia less forgiving, so want the SPH to accommodate the presbyopia. But the PD issue seems more forgiving: it strikes me that everyone'due south single-vision altitude glasses uses Dist PD as PD, and everyone wears them for all distances from infinity to virtually with no PD issues. So maybe using Dist PD equally PD is the more "natural" or amend style, if the glasses are going to exist used for multiple distances effectually the house like with my old glasses, which used Dist PD as PD? Or, is this incorrect?

If simply using Dist PD (64mm) for the PD isn't advised, I could split the difference and use 63mm (optimal for 67" WD) or 62mm (optimal for 32" WD). To me, using 61mm (a full 3mm less than the Dist PD) for the PD seems farthermost if I promise to employ the glasses at multiple distances, and because my one-time glasses which worked at multiple distances used Dist PD. But I might be understanding this wrong.

I sympathise if the glasses truly are meant to be single-purpose, for simply a xix" working distance, so in that location's no reason not to set PD for that distance. Simply my old spectacles seem to advise the new glasses tin can work at multiple distances, and if the eye can tolerate (or if the eye is used to?) the glasses' PD beingness set up to Dist PD fifty-fifty when the eye is looking at near or intermediate objects, is it more natural or amend to set Dist PD every bit PD? Or not?

Definitely welcome people's advice or opinions on this.
I should say that reckoner altitude is yet the beginning priority, so if PD needs to be set to computer distance for calculator distance to work well, I'll do it, but I got an impression from my old glasses that PD doesn't demand to be set up to the specific distance.

I read that ANSI tolerance for PD in single vision glasses is 2.5mm, simply don't know if I understand this correctly and likewise read some people consider 2mm to be significant.

Give thanks so much.