Pupillary Distance

What Is Pupillary Distance When Ordering Glasses? A Simple Guide

If you’ve ever ordered glasses online, you’ve probably come across the term “Pupillary Distance” or PD. And if you’re wondering, “What is pupillary distance when ordering glasses?”—you’re not alone! Let’s break it down in the simplest way possible so you can feel confident while buying your next pair of glasses.

What Is Pupillary Distance (PD)?

Pupilliary Distance (PD)

Pupillary Distance (PD) is the distance (in millimeters) between the centers of your two pupils. It helps opticians position the lenses correctly in your glasses so that your eyes align perfectly with the center of the lenses. This is essential for accurate vision correction.

In simple words: PD ensures your lenses are made just for your eyes.

Why Is PD Important?

When your PD is correct, your eyes look through the optical center of the lenses. If it’s wrong, you may experience:

• Blurry or distorted vision

• Eye strain or headaches

• Difficulty focusing, especially with high-power or progressive lenses

That’s why knowing your correct pupillary distance is just as important as having the right prescription.

Types of PD

There are two types of pupillary distance:

1. Binocular PD – The total distance between your pupils (e.g., 62 mm)

2.    Monocular PD – The distance from the center of your nose to each eye (e.g., 31 mm / 31 mm). This is especially important for bifocal or progressive lenses, where precision matters more.

Types of Pupilliary Distance

How to Measure Your PD at Home

If your eye doctor hasn’t provided your PD, you can measure it at home using just a ruler and a mirror:

Steps:

1. Stand about 8 inches away from a mirror.

2. Hold a millimeter ruler just above your eyes.

3. Close your right eye and align the “0” on the ruler with the center of your left pupil.

4. Without moving the ruler, close your left eye and open the right eye.

5. Note the mm number that lines up with the center of your right pupil.

That number is your PD! Most adults have a PD between 54 mm to 74 mm.

Ask Your Optometrist

If you're unsure or uncomfortable measuring at home, your optometrist or eye care provider can measure your PD accurately. Just ask them to write it down when you get your eye prescription—it’s your right to have it!