How to enter your PD when ordering glasses online
Every online glasses store asks for your pupillary distance (PD) during checkout, usually on the same page where you enter your prescription. Here is exactly what to put in that field, for every situation.
If the store asks for one number (single PD)
Enter your total distance PD, for example 63. Most adults fall between 54 and 74 mm. If you measured with PDgo, this is the big number on the result screen.
If the store asks for two numbers (dual PD)
Enter the right-eye and left-eye values separately, for example 31.5 / 31.5. Dual PD is more precise because most faces are slightly asymmetric. PDgo shows both values under your total PD. If you only know your single PD, dividing by two is an approximation the store will accept, but measured per-eye values are better, especially for progressive lenses.
If you are ordering reading glasses
Some forms ask for a near PD. Your eyes converge when looking close, so near PD is about 3 mm smaller than distance PD. If the form has only one PD field and you are buying dedicated reading glasses, use your near PD. PDgo includes a near-PD reference with every measurement.
If your prescription has no PD on it
That is normal. In many places the PD is considered part of the fitting, not the prescription, so the prescriber leaves it off. You have three options: call the optician who last fitted you, use a free on-screen ruler, or measure automatically with the PDgo app in about 10 seconds.
Common mistakes to avoid
- Guessing "average". Entering 63 because it is common can misplace your optical centers by several millimeters.
- Mixing up near and distance PD. Distance glasses need distance PD.
- Using a years-old measurement for kids. Children's PD grows; re-measure before each new pair.