Hey, it’s Emily from the Sunglass Underground® and our sister company, iGlass Underground™.  Did you know a lot of people don’t order glasses online because they don’t know their PD number, or even what it is?

Let’s explain PD and a few easy ways to get your PD number, so everyone can start saving today!

PD stands for Pupillary Distance, it’s the distance between your pupils, the center of your eyes. It’s important because we want the optical center of the lenses to sit directly in front of your eyes. This will give you the best vision.

And the cool thing about knowing your pupillary distance is: it never changes if you’re an adult. Once you know it, you know it!  Your PD is usually on your prescription, but if you don’t have it, don’t worry. You can measure it with the PD ruler you can download from our website.

If your PD is on your prescription, it may be written as one number or two. One number is the distance, measured in millimeters, between your pupils, 62 for example. Two numbers, is the distance from each pupil to the center of your nose. This measurement is often used when the distance from your pupil to the center of your nose is different for each side, for example, 30 on the right side and 31 on the left side.

Luckily, measuring your PD is easy. With our PD ruler you can take the measurement yourself, or with a friend. If a friend is helping, fold the ruler to the side that says “This Side with a Friend.” Have them hold the ruler level, above your eyes, and align the zero with the center of your right pupil, while you focus on something about 10 or 20 feet away to keep your eyes steady.

They should cover their left eye when they read the measurement. The number directly over the center of your left pupil is your PD. Repeat this a few times to make sure the reading is accurate and consistent.

You can also use any ruler with millimeter markings.  This is the side of the ruler opposite the inch markings that you probably never look at.

It’s also very easy to measure your PD by yourself.  All you need is our PD ruler and a mirror. Use the side of the ruler labeled for “mirrors”; and stand about 8” away from your mirror. Hold the PD ruler over your eyes, centering the zero over your left pupil.  When centered, cover your left eye. The number directly over your right pupil is your PD.

And that’s it!  You’re done!  This is Emily from the Sunglass and iGlass Underground™, where, “The more you know about lenses, the better we look!™”