What Is PD (Pupillary Distance)?

Measuring Pupillary Distance

The measurement of the distance between the two centers of the pupils in each eye is referred to as the papillary distance or PD. PD is an important aspect that optometrists depend on for making prescription glasses. The pupillary distance is noted by the optical technician during the eye exam, to ensure that the right concentration of the prescription lenses is in front of your eyes. If the PD is not measured by the technician for any reason, you can measure it on your own.

Measuring your Pupillary Distance (PD):

  • Stand in front of a mirror and look straight into it.
  • Hold a mm ruler under your eyes, place it on your nose bridge for accurate reading.
  • Close your right eye and align the ruler’s “0” to the center of the left pupil.
  • Hold the ruler’s position. Close your left eye. Read the measure of the ruler at the center of your right pupil.
  • Repeat these steps several times and use an average for better accuracy.

Alternatively, you could also have a friend measure the PD for you. Note that the average PD for adult is between 55 and 68mm. For bifocal and progressive lenses, you will need two PD values. For accurate reading in case of multi-focal and progressive lens, we recommend that you get your PD from an eye care professional.