Inter Pupillary Distance ruler

Source: https://www.thingiverse.com/thing:3753907 SummaryIf you want to order glasses online, you'll need to know your pupillary distance - and it's not typically included on your vision prescription. Use this scale to measure the distance from the bridge of your nose, to the center of each pupil. The numbers on the scale are in millimeters, and are printed in reverse so they're more easily read in a mirror.