Two Ways to Measure PD

Single (Binocular) PD

This is the most common PD measurement and is used for most RX eyewear except reading glasses. Keep your child's head as still as possible and put the zero of a millimeter ruler over the center of the right eye's pupil and measure to the center of the left pupil. That's it!

Dual (Monocular) PD

Monocular PD is the distance from each pupil to the bridge of the nose in millimeters. Added together, you should get the same number as a single PD measurement. Dual PD is always written with the right eye first (OD) and the left second (OS) like this: 29.5/32.5 (which is the same as 62 single).

Use Our Ruler to Size It Up

Pupillary distance (PD) is the distance between the center of the pupils in both eyes, measured in millimeters. The PD should line up with the center of the lenses to provide the best visual acuity. Download our PD ruler and print it full size to measure your kiddo.

OMG! This is Too Hard!

Okay, Mama bear. Here's a tip. Many optical professionals will measure your kiddo's PD either free or for a nominal charge. Or try an app like Eye Measure or GlassifyMe with older kids.