What is PD and can I measure it myself?

Pupillary distance or PD is the distance between the centres of your pupils and it is measured in millimetres. The PD number can be given separately for the right and left eyes (two PD numbers on the prescription) or as a total pupillary distance (one PD number on the prescription). It is recommended that the distance be measured at an optician, and this is usually done when the prescription is issued. PD is required to determine the centre of the eyeglass lenses, which is the point of sharpest vision.
If the prescription does not include a pupillary distance value, it can be measured with the help of a ruler. It is recommended to have it measured by someone else, but you can also do it alone in front of a mirror. You should stand in front of your partner or mirror, the ruler placed parallel to the eyebrows so that the ruler’s zero point is in the middle of the pupil of the left eye. The PD value is the number at which the centre of the right eye’s pupil is located on the ruler.
Alternatively, place the ruler on your forehead, parallel to your eyebrows, so that your eyes are visible under the ruler. Do not bend the ruler against your face and ask your partner to take a picture from a distance of about 2 metres. Send the picture together with your name to [email protected]