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 ...

Add Yahoo as a preferred source to see more of our stories on Google. You’ve no doubt heard the carpentry proverb “Measure twice, cut once” and may even have made it a mantra for your own projects.

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