You will see that a lot of prescriptions, especially bifocals and progressives need "PD" measurements. Here's what you need to know about PD or Pupillary Distance.
What is Pupillary Distance (PD)?
A personalized fit starts with measuring your pupillary distance-that's the space between the centers of each of your pupils. It's measured in millimeters and tells the lens maker where to put the optical center on each lens. You can ask your eye doctor to include your PD measurement on your prescription,
Don't have a PD? No problem! Simply send us a selfie of yourself wearing your new frames and looking straight into the camera.
Measuring your PD at home
to download the above instructions in PDF format
What Is Single Vs Dual PD?
SINGLE PD is the pupillary distance between the center of one pupil to the other, which can be a distance PD or near PD. Distance PD can be used to order any type of prescription glasses except reading glasses. Read below to learn how to calculate near PD for reading glasses.
DUAL PD, or monocular PD, consists of two numbers and is the distance between the centers of each pupil to the bridge of the nose. Dual PD is usually written in the following notation: 33/31, where the left number is the left eye measurement and the right number is the right eye measurement.
How Do You Calculate Near PD For Reading Glasses?
You can calculate Near PD for reading glasses by subtracting 3mm from your distance PD. For example, if your distance PD is 63mm, then your near PD is 60mm.If you are using Dual PD to calculate near PD, then subtract 1.5mm from each eye’s measurement. For example, if your dual PD is 33/31mm then your near PD would be 31.5/29.5mm.