On your prescription

Measure your PD without an Eyecare Professional Even if your Eyeglasses Prescription didn't include your Pupillary Distance, you'll still need to know it before you order your EyeBuyDirect glasses. We'll show you how to measure it!

Hi there, today we are going to learn how to measure your pupillary distance, or PD. PD is the distance in millimetres from the center of one pupil to the center of the other. This is really important because each lens has an optical center that needs to be placed directly over your pupil. Now this is really easy to do. All you need is a classroom ruler and a mirror. So, let’s get started.

So, you’re going to want to look straight into the mirror, and put the ruler over the bridge your nose. You’re going to put one end so that it aligns with your left pupil and then measure the distance between your left and your right pupil.

You’re going to want to do this several times until you’re happy with it’s accuracy. You can always ask a loved one to help you. Or you can help someone else. Are you ready Bob?

Make sure they’re standing still, put the ruler on their nose, and measure the distance from the center of the left pupil to the center of the right pupil. Your PD is 32. That’s not in the normal range because you’re a cat.

Normal PD ranges for humans range between 57 and 65 millimetres, with the average falling about 63.

Now sometimes your PD will be written as two numbers, say 63/61. The first number is your far distance, and the second number is your near distance. If you’re ordering just single vision lenses, then you only need your far distance. But if you’re looking for progressives or bifocals, then you’ll also need your near distance.

That’s it. Good luck measuring! Bye!

PD or pupillary distance refers to the distance in millimeters between the center of one pupil to the center of the other. Having a correct PD on your glasses prescription insures that you are looking through the ideal spot in your lenses. If this number was not provided on your prescription by your eye care professional, you can measure it yourself.

How to read your prescription

Do it yourself!

  • Place a mm ruler directly under the center of your right or left pupil so that the ruler is horizontal. Stand in front of a mirror, or ask someone else to measure for you.
  • While looking straight ahead, measure the distance from the center of your left pupil to the center of your right pupil.
  • Repeat for accuracy.
Prescription example

Use an average

Note that the average PD is between 57 and 65mm, and an average of 62mm. For bifocal and progressive lenses, two PD values are needed. In these cases, EyeBuyDirect recommends getting your PD directly from your eye care professional.

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