How Do I Measure Near PD for Bifocals?

Pupillary distance, or PD, is the distance from the middle of your right pupil to the middle of your left pupil. The distance in between your pupils is measured in millimeters. According to Opticsplanet.net, knowing the measurement between your pupils for bifocals is important because the "measurement is used to accurately center the lenses in the frame that you have selected." Measuring your near PD is often done by a licensed optician, but you can easily measure the distance of your pupils yourself.

Things You'll Need

• Millimeter ruler

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Instructions

• 1

  Stand an arms length away from a mirror. You may also want to enlist the help of a friend to measure your PD.

• 2

  Place a millimeter ruler across the bridge of your nose. The "0" mark should be aligned perfectly with the middle of your right eye if a friend is going to measure your PD for you. If you're looking a mirror, it may be easier to align the "0" mark of the millimeter ruler with the middle of your left eye.

• 3

  Measure the distance between the middle of your right pupil and the middle of your left pupil. Write your PD down. According to Opticsplanet.net, the average adult PD measurement is between 58 mm and 70 mm.