How To Clean Your Eyeglasses | SmartBuyGlasses IN

What is pupillary distance? (and how do you measure it?)


Did you know, you can have any pair of glasses in the world, with the perfect prescription, but for sharper vision, you need to have an accurate Pupillary Distance measurement? “What’s a pupillary distance”, you may ask? A frequently asked question that all glasses wearers should know the answer to, in order to make sure that their glasses are doing their important job.


The effects of an incorrect pupillary distance can be highly distressing, causing symptoms that can have an impact on everyday activities. Not knowing why these symptoms arise can be even more stressful, which is why we’re going to highlight all of the central pupillary distance questions, and answers, that everyone should be informed of. 


What is the pupillary distance?

Pupillary Distance, also known as PD, is the distance between your pupils in millimeters - simple as that. Calculating your pupillary distance is typically done by your eye doctor or specialist, as the measurement is crucial in fitting your glasses to your eyes. You may be familiar with the concept; your optician should provide your pupillary distance after an eye exam. 


The average pupillary distance for most adults lies between 55 and 70mm, while the average pupillary distance for children is usually between 42 and 54mm. However, for some people, pupillary distance can vary outside these typical measurements.


Interestingly, you can measure your PD and discover technologies to find an accurate measurement, which we will uncover in the next question.


How to measure pupillary distance?


There are 4 ways to measure your pupillary distance, with assistance, by yourself, with the online pupillary distance measuring tool, and with the app which we will talk about later in the article.


 For the first example, we’re going to be measuring a pupillary distance with assistance. Please note that for this test, you'll need a ruler, another human, and a pair of eyes.


Here are a few starting tips that you can use when someone is helping you measure your pupillary distance:


•Have them crouch/sit while you stand so they are out of your field of vision

•Keep your eyes as still as possible

•Look above their head at something approximately 10-20 feet away


Step 1 – Hold the ruler up to the bridge of your nose. Your ruler can be any millimeter ruler


Step 2 – Have a friend stand roughly an arm’s length away from you


Step 3 – Close your right eye and ensure the pupillary distance ruler’s zero is aligned with your left pupil. Make sure your accomplice is paying attention, as you'll need them for this part


Step 4 – Keep the ruler still. Look straight ahead, close your left eye and open your right eye


Step 5 – Have your friend read the number that's aligned with the center of your right pupil. This number is your pupillary distance. Remember you need the measurement in exact millimeter


Step 6 – Use the scientific method: Repeat the process to ensure the most accurate result.​​​


For the next example, we will look into how to measure pupillary distance by yourself. Please note that for this test, you'll just need a ruler and a mirror. Nice and easy.


Step 1 – Hold the ruler up to the bridge of your nose. Your pupillary distance ruler can be any millimeter ruler


Step 2 – Face a mirror


Step 3 – Close your right eye. Whilst looking in the mirror, ensure the pupillary distance ruler’s zero is aligned with your left pupil


Step 4 – Keep the pupillary distance ruler still. Look straight ahead, close your left eye and open your right eye


Step 5 – Read the number that aligned with the center of your right pupil. This number is your pupillary distance. Remember you need the measurement in exact millimeter


Step 6 – Repeat the process to ensure you get the most accurate result


If you need a visual guide, please refer to the video mentioned above, or take a look at this step by step image, below:

Lastly, If you want to measure your pupillary distance the fast way, then you can swiftly and easily do this online with SmartBuyGlasses, with the advanced online pupillary distance measuring tool. 


All you’ll need to do is head to the PD measuring tool online, grab a regular magnetic credit card, have access to a webcam via phone or laptop, and sit back, relax, and listen to the instructions! 


Please refer to the image below for step by step instructions: 


What happens if PD is wrong on glasses?

This is one of the most important questions that we wanted to cover. It’s important to note that even a slight error in measuring the pupillary distance can cause frustrating eye problems, and will need to be corrected as soon as possible. Please note that you shouldn’t ignore any symptoms or an inaccurate pupillary distance.


Most people go some periods of time with an inaccurate pupillary distance, not knowing what the pupillary distance is, and suffer the consequences with symptoms they can’t find answers to. 


Having an inaccurate PD can cause eye strain from a distorted view that the glasses are providing, due to the incorrect PD. This can also lead to headaches, blurry vision, and fatigue. All of these symptoms can progress and cause an ongoing feeling of lethargy, which leads to a lack of energy and disorientation. 


You couldn’t imagine how much a pupillary distance could affect your eyes and general health, right? If you have any of the following symptoms or have a feeling that your glasses are just not ‘feeling right’, know that this can, and must, be resolved. 


You can first start by measuring your pupillary distance online, and contact your eye doctor/optician with an appointment, explaining how you feel. 


Is there an app to measure pupil distance?

You’ll be happy to hear that the answer is yes! You can now measure your pupillary distance online with the Lens Scanner, available on the App Store and Google Play. This app will help you save time and money when buying a new pair of glasses.


The application allows you to get your current prescription details free of charge within minutes without having to go to an eye doctor. The Lens Scanner is also a pupillary distance measurement app, so you will get all the details you need to buy a new pair of prescription glasses


Here are a few benefits of using the Lens Scanner app to measure pupillary distance online:

• The application is totally free

• It's fast and hassle-free as you can get it done in only 5 to 10 minutes

• You can get your own prescription anywhere and at any time

• It's an FDA listed application

• You can immediately start shopping for a new pair at SmartBuyGlasses!


How to Measure PD Using the Lens Scanner App:

To find your pupillary distance using the Lens Scanner app, all you need is a smartphone with a functional camera, a magnetic card, and a computer (desktop or laptop) with a 12” screen or larger, and a pair of prescription glasses.  Download the app and follow these three easy steps:


1. Scan Your Lenses – Sync the app with your computer and follow a few easy steps to scan your lenses. It's simple to use and laid out with you in mind, but if you have any queries, don't hesitate to email us here

2. Get Your Prescription and Pupillary Distance – You'll get your accurate prescription details completely free of charge. Hold a magnetic card on your forehead above your eyebrows and snap a selfie so our Lens Scanner can measure your PD

3. Buy Prescription Eyewear – Shop the extensive collection of designer eyewear at SmartBuyGlasses with a 2-year warranty, FREE shipping, 100-day returns, and the best price guarantee.



You now know that the pupillary distance (PD) is simply the distance between both of your pupils and that having an incorrect PD can cause distressing symptoms, which need to be addressed as soon as possible. 


Now that you can measure your pupillary distance online, with and without assistance, and on the SmartBuyGlasses Lens Scanner app, you can leave confidently knowing that you have all the information you need about your pupillary distance, and how to purchase glasses with the correct measurements in the future.


If you’re looking to change your frames with an accurate PD, all you have to do is select your new glasses with your newly calculated PD value. Now that you have the best measuring tools and techniques, which one will you use?