How to measure your PD/pupil distance.
Your PD measurement should be part of your prescription, but sometimes you may find this information missing from your prescription. If it is missing either contact your optician as they should have a record or alternatively take the measurement yourself.
It’s easier if you ask a friend/family member to help you, but it is possible to do it yourself using a mirror as explained below.
Place a millimeter ruler on the bridge of your nose.
Have a friend face you about arm’s length away.
Have your friend measure the distance between the centers of your pupils (the black dots in the middle of your eyes).
TIP: This should be done with glasses off, if the numbers on a ruler are difficult to see, then a magnifying mirror may help.
Whilst looking into a mirror hold a ruler against the bridge of the nose with one hand.Close your left eye, and line the '0' up with the center of the pupil of your right eye as shown in the diagram. Without moving your head or the ruler open the left eye and close the right eye. Read the number that line up with the center of the pupil of the left eye. This number represents your Distance PD in millimeters. You have just used this technique to measure your distance PD.
Repeat this whole process at least 3 times to try and get a consistent measurement in millimeters. Make sure your head and the ruler do not move after lining up the zero on the ruler until you take the reading. This procedure may be difficult if one eye has very poor vision compared to the other eye.
HOW YOUR PD MAY BE WRITTEN
For regular single vision glasses, you will generally see the PD as a single number often in the 56 to 62 range such as “61,” although some opticians may describe the measurement with two numbers, 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/distance PD is 63 when the eyes are straight forward and 62 when there turned inward at a “close-up” angle such as for reading.