PD stands for PUPILLARY DISTANCE. The PD is the distance from the centre of one pupil to the centre of the other.
This measurement is used to ensure proper lens placement within your frame.
If you would like to measure your PD at home all you need is a mirror and a ruler. You can carry this out yourself or alternative ask a friend or family member to take this measurement for you.
If you are still unsure most optical stores will measure it for you. If however, for any reason you are not able to obtain this measurement don't worry! We use an average PD measurement of 63mm for distance and 60mm for reading which has been set as standard by our Dispensing Opticians.