Your PD is the distance between each of your pupils. This measurement is necessary to ensure the correct positioning of your lenses within the frame you have chosen. Your PD can easily be measured in three simple steps.
This video explains what a PD (Pupillary Distance) is and how to measure it.
You can do it yourself simply by looking in the mirror. If you need your glasses on to do this, you can draw dots on the lenses where your pupils are (using a magic marker or highlighter); then take the glasses off and measure the distance between them.
You can also get this information from your doctor or from a licensed optician.
If you have two PD numbers on your prescription, you have either been given both the Distance/Reading or Right Eye/Left Eye.
Here's what you do:
Two same number: (Ex. 30/30) Add them together (Ex. 60 is your PD).
Two low numbers*: (ex. 30/31) The first number is for the right eye (O.D.) and the second number is for the left eye (O.S.). *Place it in the "Customer notes" section of the order form.
Two high numbers: (Ex. 62/59) First number is your Distance PD and the second is your Near PD (for reading-only glasses).
As a Guideline: Most adults' PD's are between 55-65. Most kids' PD's are between 42-54.