Your PD or pupillary distance is the measurement from pupil to pupil.
On your prescription, your PD may be written as one number ( IE: 64), or as two numbers ( IE: 31/32). We need this number to ensure that your glasses work properly. If you do not see your PD on your Rx, don't worry. We are able to accurately measure your PD using our patented photo measurement process. For more info, visit: https://davidkind.com/optics