The pupillary distance (PD) measurement is a requirement for people who want to purchase eyeglasses. Here, find out how to measure your PD using a mirror and a ruler. Share on Pinterest Some eyewear ...

Pupillary distance is the space — measured in millimeters (mm) — from the center of one pupil to another. When you need glasses, an optometrist or an optician will measure this distance to make sure ...

Measuring distances accurately has become significantly easier with the advent of smartphone technology, particularly with the array of distance measuring apps available for both Android and iPhone.