How to measure PD or Pupillary Distance
Your PD or Pupillary Distance should be ideally included with your eye doctor’s prescription so you have ready access to it, because it is important for your maximizing comfort with the design of any lines you may have.
The PD is simply the measurement in terms of millimeters or mm between of each eye as pictured below.
Some may invite you to have a friend help you to measure your PD with a ruler for mm across your nose, or for you to do so on your own by standing close to a mirror, making a few PD measurements, and then perhaps choosing the average of the distances you have come up with.
ZipOptical strongly encourage you to have your PD determined professionally, particularly if you are ordering progressive, bifocal, or prescription reading glasses.
For regular single vision glasses, you will generally see the PD as a single number often in the “50’s” to “60’s” range such as “61,” although some eye doctors may describe the measurement with two numbers about have that size and differing slightly, such as “30/31.” In this case, “30/31” would mean a PD of “61” with “30” and “31” referring to the separate distances between the center of the nose and each eye.
After you reach adulthood, your PD generally remains the same, allowing you to use the PD shown on an older adult prescription of yours if your latest one does not show it.
Most prescriptions only show a PD with a single, two-digit number. However, the PD’s for progressive and bifocal lenses are generally measured in terms of two, two-digit numbers like “63/62.” This means that the general PD is 63 when the eyes are straight forward and 62 when there turned inward at a “close-up” angle such as for reading.
A sample eyeglasses prescription, and how to input the rx online
You can download a printable paper ruler here, provided by vendian.org. Remember to disable any zooming before printing.