Practical Tips: How To Measure Pupillary Distance With Precision

Ordering glasses online is quick, simple, and fun, but you’ll need an accurate prescription for the perfect pair.

Pupillary/pupil distance (PD) is one of the keys to success when shopping for a new pair of glasses, but it’s not always listed on your prescription card from an optical center. That means you might need to measure the distance between the pupil in your left eye and your right eye to get prescription glasses that feel just right.

PD matters a lot. An inaccurate measurement can end up with glasses that don’t feel right and might even cause headaches and blurred vision. Don’t let that stress you out — Pair is here to help you learn about accurate and precise PD measurements.

What Is Pupillary Distance?

Pupillary distance, or PD, is the measurement of the distance between the centers of each pupil. It’s typically measured in millimeters and is a standard part of an eye exam in most cases.

For adults, the average pupillary distance, or average PD, is between 54 and 74 millimeters.

If an eye doctor measures your PD, they’ll check for both binocular PD, the distance between the center of your right pupil and the center of your left pupil, and monocular PD, the distance from the centers of each pupil to the bridge of your nose.

If necessary, they can also check your near PD and distance PD, which measure the distance between your pupils when looking at something close and far away, respectively.

Binocular PD is usually the only measurement needed for typical prescription lenses. Monocular PD is used for more specialized prescriptions. For the purposes of this article, we’ll focus on binocular PD.

Why Does a Pupillary Distance Measurement Matter?

A correct pupillary distance measurement helps you get a pair of eyeglasses that do exactly what you need them to do. An accurate PD measurement positions the center of your prescription lenses directly in line with your pupils, ensuring that you are looking through the correct part of your lenses. This helps you avoid uncomfortable issues like eye strain, blurry vision, and headaches.

Most of all, the wrong PD measurement can make it harder to see through your glasses. This issue can be inconvenient at best and risky at worst. Clear vision is necessary for activities like driving, and an incorrect PD measurement could put you in harm’s way. That’s one more reason to ensure this measurement is 100% accurate.

All in all, pupillary distance is just as important as the broader details of your prescription. Without it, you might wear prescription glasses that are otherwise right on the money yet still worsen your vision.

How To Measure Pupillary Distance

You can go to an eye care professional to measure your pupillary distance, but you can also do it at home. There are a few quick and simple ways to measure your pupillary distance, be it solo or with help from a friend or family member.

Use a Millimeter Ruler

If you have a ruler that measures in millimeters and a mirror close by, you’ve got everything you need for a DIY PD ruler. Ensure you’re in a well-lit area, then hold the ruler against your brow line. Close your right eye and hold the 0 mm mark up to your left eye, centering it on your pupil.

Now, it’s time to measure the distance between your left and right pupils. Hold the ruler steady and open your right eye, closing your left eye at the same time. Find the millimeter measurement on the ruler that lines up with your right pupil, right in the middle.

This number is your pupillary distance, and if you already have a prescription from an optometrist, you can use it to order your new glasses right away.

Use an App

If you don’t have a ruler handy, no worries; you can measure your PD with help from a free app or online tool. Apps for eye measurements are easy to use and can get you a quick and accurate measurement using the camera on your phone.

Get a Professional Measurement

A professional optician is the best person to help you with any measurements you need for your glasses. Since a PD measurement is a regular part of an eye exam, you might want to wait for your next appointment to get the most accurate prescription for your glasses.

Do You Need Monocular or Binocular PD Measurements?

Most prescriptions call for only a binocular PD measurement rather than a single PD for each eye. Binocular or dual PD is the norm, but it’s worth asking your eye doctor about the nature of your prescription before defaulting to binocular PD.

What if Your PD Isn’t on Your Prescription?

When you finish an eye exam, your eye doctor will give you an updated prescription card, which usually tells you everything you need to know to order glasses online. But sometimes, your eye doctor’s office might forget to print the PD on the card or omit it for other reasons.

If you can’t find your PD on your prescription card, contact your eye clinic. They most likely have the measurement on file from your last eye exam and can send it to you.

What if You Get Glasses With the Wrong PD?

Mistakes happen, and it’s easy to accidentally mess up one of the details on your prescription when ordering glasses online.

We get it, so we offer free returns on everything you order. If your glasses don’t fit right or feel the way they should, we’re happy to give you a refund. From there, you can double-check all your numbers and order a pair that perfectly matches your prescription.

How To Choose the Right Glasses for You

Once you have your pupillary distance and other necessary measurements, it’s time to pick out a pair of glasses. Pair makes the whole process easy with virtual try-ons and plenty of options. Here’s how to make shopping for glasses as simple and fun as possible.

Know Your Other Essential Measurements

Choosing the right frame size and lens type are just two aspects of picking out the perfect pair of glasses. To get everything correct, you’ll most likely need a recommendation from your doctor and precise head measurements.

Pair takes the guesswork out of sizing for glasses with easy-to-read measurements. Refer to these numbers, which you can find on each of our product pages, to get a clear sense of whether a pair will fit you.

Know Your Style

Glasses are about more than just accessibility. They can upgrade your look instantly and make you feel like a brand-new version of yourself. That’s why we encourage you to take your time, make the most of our virtual try-on feature, and explore all the styles Pair offers.

Give your glasses an even more personal touch by customizing them with our magnetic Top Frames. These unique accessories seamlessly latch onto your base frames, giving them a new look. You can even use our Sun Tops to switch from wearing glasses to sunglasses instantly.

Save Your Prescription for Later

If you order a pair of glasses from us, we’re confident you’ll return for another. That’s why we recommend saving your prescription on your Pair account. You can refer back to it and update the details whenever you need to. That way, you’ll always have your prescription info handy.

Measure Your PD for the Perfect Pair

Pupillary distance might not sound important, but it can be the difference between comfortable glasses and round-the-clock eye strain. If you feel something is off with your prescription, talk to your eye doctor and ensure you have a correct PD measurement.

You can use the simple steps we outlined to measure PD at home, but it never hurts to loop your eye doctor into the process, especially if you’ve had issues with inaccurate prescriptions in the past.

Visit the Pair shop now to choose your new glasses and instantly level up your look. Remember to add some Top Frames to your order to give yourself plenty of options that work with any outfit in your wardrobe. With Pair, there’s eyewear for every mood and moment.

Sources:

Eyestrain - Symptoms and causes | Mayo Clinic

Eye Exam and Vision Testing Basics | American Academy of Ophthalmology

Pupillary Distance: What It Means & How To Measure | Cleveland Clinic

How to Read an Eyeglasses Prescription | American Academy of Ophthalmology