Your PD isn’t part of the prescription. But the prescription itself must be provided to you by law in the US.

For anyone near a Warby Parker, they'll happily measure your PD in about 30 seconds. Measurements can vary slightly so you might want to do it a few times and average them.

You can also do it online with Warby Parker as long as you have a credit card (to hold under your face; not to pay with).

do they also need the picture of the backside and home zipcode?

if not, sounds like a startup idea.

Now that is a clever way of doing it!

The PD also varies a bit from reading glasses to distance glasses. If you are ordering single vision glasses, you might want to collect both numbers.

Weird. I’m in Mississippi, of all places, and, without asking, my optometrist always sends me off with a printout containing my prescription and PD.