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 ...

Forget hunting for a tape measure or a protractor. Use your Android phone camera and sensors to handle different types of measurements easily.

You may have seen surveyors (or maths students) running around with measuring wheels, counting the clicks to measure distances. [AGBarber]’s digital measuring wheel works in much the same way, but ...