Pupillary Distance (PD) is the distance between your pupils – usually measured in millimeters.
The optical center of the lenses gives you the truest vision. This part of the eyeglasses should be directly in front of your pupils.
To get the correct positioning of the lenses on your eyeglasses, the eyeglasses lab needs your PD.
Pupillary distance generally falls between 54 and 68 mm.
It can be tricky to measure your own PD. It is best to have it measured by a skilled optician.
Optometrists will note this measurement during your eye examination but may omit the PD from your prescription because it gives consumers the ability to shop online. Ask them to write this number in your prescription, if they haven’t already.