Pupillary Distance (PD) is the distance between the centers of the pupils in each eye, usually measured in millimeters.
Your PD can be measured by your doctor during your eye exam or an optician can provide this to you, sometimes for a minimal charge. This is normally done with a small millimeter ruler or with a optical device called a pupillometer.
It is always best to obtain this measurement from an eyecare professional. If you do not have this measurement, however, you may choose to measure your PD yourself using the millimeter side of a ruler, or there are also mobile phone and web apps that can assist you.
If your prescription does not contain your PD:
- An optical shop take this measurement for you – some may charge a fee for their time and expertise.
- Contact an optical shop where you have bought glasses in the past. Again, there may be a fee for this information.
- Call your optometrist. He may have a record of your PD.
- You can try measuring your own PD, but it may not be as accurate. We recommend that you obtain a professional PD measurement whenever possible.
How to Measure your own PD:
- Remove your glasses if you are wearing any.
- Stand about 8 inches from a mirror. Hold a ruler using the millimeter side against the bridge of the nose with one hand.
- Close one eye.
- Line the ‘0’ to the centre of the pupil of your open eye.
- Without moving your head or the ruler open the other eye. Close the opposite eye.
- Read the number that lines up with the center of your pupil. This number represents your PD measurement.
You may want to do this several times to make sure you get a consistent measurement.