Want to measure your PD yourself? Download and print our free PD ruler!
Ordering a new shiny pair of glasses? Great! Then you’re going to need your Pupillary Distance to make sure that your new specs fit your face perfectly.
Dubbed ‘PD’ for short, Pupillary Distance is a very important measurement that you’ll need to provide any eyewear provider whenever you order new glasses. You can usually find your PD on your official eyewear prescription, but if you’ve misplaced it - don’t worry.
We’ll explain in this article what a PD is and how to easily measure it for yourself from home.
What is pupillary distance (PD)?
Simply put, your Pupillary Distance is the distance between the center of your left pupil to the center of your right pupil. Makes sense, right?
PD is usually measured in millimeters. To give you a rough idea, the Pupillary distance of an average adult is between 54-74 mm whilst children often have PD readings between 43-58 mm. However - everyone’s face is different! For instance, research suggests that males typically have a slightly higher PD than females.
Why does your PD matter?
Knowing your PD is really important, as you’ll need it to ensure you’ll be able to see comfortably out of your brand new glasses.
PD helps glasses providers determine the ‘ideal spot’ for your eyes to look through in your glasses. We use this to align your prescription right in front of your pupils, which ensures your vision is clear and optimally corrected.
Of course, this means that your PD needs to be as accurate as possible as getting the PD wrong can cause eye strain or headaches.
3 easy ways to get your PD
So now you know what a PD is, let’s find yours.
It’s really very easy. Here are the 3 easiest ways to get your PD:
There’s a key difference between the way you measure PD for regular glasses, and reading glasses! If you’re looking to purchase reading glasses, make sure you scroll down a bit lower to read the section called ‘Getting Your PD For Reading Glasses’.
1. How to read your PD off your eyeglass prescription
The most accurate way to get your PD is to check your eyewear prescription that you received from your optometrist or ophthalmologist.
It’s also important to make sure you’re checking a recent eyeglass prescription. Adult PDs usually remain stable, but for children and teenagers who are still growing, their PDs will change over time.
To find your PD on your prescription, just look for the numbers beside the letters ‘PD’.
In the case above, the PD is 57 mm.
Single PD vs Dual PD
Typically a PD reading consists of just 1 set of numbers. However, in some cases, 2 sets of numbers are given. In this case, the optometrist/ophthalmologist you visited uses Dual PD, which means the Pupillary distance was measured from the center of each pupil, to the center of your nose.
Dual PD will have a set of numbers for each eye, which is typically marked as ‘right’ and ‘left’. In some instances, you might come across OD and OS, which just also means Right Eye and Left eye.
For example, instead of saying your PD is 65, your prescription may say:
- PD for OD: 32.5
- PD for OS: 32.5
It’s also entirely possible to have different PD measurements for each eye. This is because our eyes are often not perfectly symmetrical on our faces. Some people may have one pupil that’s slightly further away from the bridge of their nose than the other pupil - for example, due to the proportions of their face, or from a condition such as an eye turn. In such cases, providing a dual PD measurement is the best way to ensure your eyeglasses fit your face perfectly.
2. How to measure your PD yourself in 3 easy steps
If you can’t find your PD on your prescription (or if you can’t find your prescription!), it’s very easy to measure your PD from home.
To measure your PD manually, you’ll need 2 things:
- A ruler (preferably one with millimeters)
- A mirror
With your ruler in hand, stand about 8 inches away from a well-lit mirror. With your face straight and staring ahead, hold the ruler up against your brow over the bridge of your nose.
Next, keep your right eye shut, and line up the beginning or ‘zero’ of the ruler to the center of your left pupil. While keeping your eyes dead straight, open your right eye and shut your left eye.
Now, with your right eye open, you should be able to see the number on the ruler that lines up to the center of your right pupil. That’s how you measure your pupillary distance. Make sure to write down that number!
You’ll want to perform this process 3 or 4 times to ensure that the number is correct and accurate.
Remember, the PD range of an adult is between 54 – 75 mm while a child’s PD can range anywhere from 43 – 58 mm. If your own PD is wildly different from this - double check you are reading the ruler properly.
Or, download and print this ruler
If you don’t have a millimeter ruler on hand, you can download and print out our PD ruler here.
3. Measuring PD is much easier with a friend
If you find it difficult to measure your PD by yourself, then grab an unsuspecting friend, family member, lover, or a kind stranger. It’s much easier to do when you’ve got an extra set of eyes around to help you!
Things you need:
- A millimeter ruler
- A friend
Stand up straight with both eyes open. Have your friend stand in front of you a little as you stare straight ahead with both eyes open.
Have your friend measure the distance from the center of one pupil to the center of the other pupil with the millimeter ruler. Make sure to keep your eyes as still as possible and avoid looking at your friend! Stare straight ahead.
Have your friend repeat the process starting from the opposite eye, to make sure that number matches up. Repeat 2 or 3 times to ensure accuracy.
Pupillary distance measurements done at home with a ruler aren’t always as accurate as the measurements you’ll receive from your eye-care professional. It’s always best to visit one and schedule an eye exam to get glasses that fit you best!
How to measure the PD for reading glasses
Measuring your PD for reading glasses requires a slight change in procedure.
That’s because your PD changes slightly when you’re looking at objects that are closer, such as a book.
However, the PD measurement technique remains largely the same.
- First, get your regular PD from one of the 3 methods above.
- Once you’ve gotten the number, subtract 3 mm from the result of your PD.
For example, if you measure your regular PD as 58 mm, you just subtract 3 mm from it to get your reading glass PD, which is 55 mm.
If your preferred method of measuring is using Dual PD then all you have to do is subtract 1.5 mm from the measurement of each eye. For example, if your Dual PD number is 30/29, then your reading glass PD would be 28.5/27.5 mm.
You’ve got your PD! Now what?
Now that you’ve gotten your PD measurements, selecting your Mouqy glasses types should be a walk in a park.
Have fun browsing our collection for your perfect Mouqy glasses, or click here if you’re ready to checkout!