Your pupillary distance (PD) is the distance between the centres of your pupils. We use this measurement for every prescription order to line up the centres of the lenses with your eyes.
If you order in-store, we will measure this for you but if you're ordering online, we'll need you to measure this yourself. You can measure your PD using a millimetre ruler and a mirror, or if you have a webcam you can also use our accurate PD measuring tool. You can find our help sheet to guide you through measuring at home, and our measuring tool here.