Pupil Distance (PD) is the distance between the pupils in millimetres. This measurement is needed when prescription lenses are being mounted in your optical frames. Most adult PD's are between 60-65mm. The average being 63mm.

To get your PD you need to either ask your Optician at the time of your eye test, do it yourself by using a mirror or ask a friend to help you.

To measure your PD yourself:

1. Stand with your face about 20cm from a mirror.
2. Close your Right eye and look only with your Left eye.
3. Place a ruler flat against the mirror and align it horizontally with the millimetre scale pointing up.
4. Look over the top of the ruler and align the zero mark in the centre of your Left pupil.
5. Open your right eye and close the left, but do not move your face or the ruler.
6. Read the millimetre measurement corresponding to the centre of your Right pupil.

To measure your PD with a friend (If you have glasses):

1. Using a non permanent marker ask you friend to stand directly in front of you and mark a dot in the centre of each pupil on your glasses.
2. Your PD is the distance between these dots in millimetres.