Pupillary Distance (PD) refers to the distance in millimeters between the center of one pupil to the center of the other. Having a correct PD on your glasses ensures that you are looking through the ideal spot in your lenses.
Measure with your phone 📱
You can measure your PD with a mobile app called GlassesOn, available for Android and iOS. It's super easy! Follow the instructions in the app and you will get your PD in a matter of seconds.
Your PD should be exact. If your lenses aren't centered correctly, they can cause discomfort and eye strain. A small margin of error might not cause problems, but it’s better to be as accurate as possible. You can repeat the process a couple of times for accuracy and use an average for your final measurement.