How to Measure Your Pupil Distance

How to Measure Your Pupil Distance

You may have noticed in our online prescription form we ask for an optional Pupil Distance value?

If you are not familiar with this term, your pupillary distance (PD) is the distance between the centres of your pupils.

Your PD can be an important part of your prescription lenses. This value will ensure you’re looking through the best spot in your lenses for clear vision.

If you know this measurement, you can select it from our drop down menu on the left hand side of your screen when manually providing your prescription information.



We always advise adding your PD value if you can, particularly if you have a higher prescription. We want to ensure you’re getting perfect vision from your new glasses.

If your PD is not included on your prescription, you can contact the optician who last tested your eyes. Legally, your optician must provide you with your prescription information if and when requested.

Similarly, if you have previously bought prescription eyewear from another store they may have this value on file for you.

However, if this is not an option for you then we recommend that you use the iPhone app ‘EyeMeasure’ or the Android app ‘GlassesOn’. These apps are easy to use and clinically accurate. You can also choose average values which are set at 60mm for women and 63mm for men.

What is pupillary distance (PD)? 
Pupillary distance (PD) is the distance between the pupils [the black dot in the center of your eye] of your two eyes. 

Why is your PD value important?
When getting new prescription glasses, we use your PD value to determine the optical center of each of your lenses. Your lenses should be aligned directly in front of the center of your pupil. If you are able to provide us with an accurate PD then we can have your prescription lenses made as precisely as possible. The more precise the measurement, the greater the comfort and clarity you will get from your glasses.

What is your PD measured in?
Your PD is measured in millimeters (mm).

What is an average pupillary distance?
The average pupillary distance for an adult is approximately 63mm for men and 60mm for women. However, this is not a number you should guess based on averages as pupillary distance can vary widely. We ask that the PD is provided for prescriptions greater than +/- 3.00 whilst lower prescriptions can be dispensed with an average value if this suits you better.

Where do I get my pupillary distance measurement?
Pupillary distance measurements are usually taken when you are being fitted for glasses after your eye exam - you can ask for this measurement to be shared with you. Your local optician will usually measure your pupil distance with a high-precision measuring device called a pupillometer. However, please be aware some opticians may be reluctant to share this information with you as it will signify your considering buying glasses elsewhere.

How do I measure my PD myself?
We recommend you get your pupil distance measurement using a free pupil distance app. The two PD apps we recommend are Glasses On which you can download from the Google Play store for Android or Eye Measure which can be downloaded from the Apple App Store for iPhone.

Both of these apps use virtual reality to accurately measure your PD quickly and efficiently. Each application will measure your pupils in millimeters which you can then record, and fill out in our online prescription form or email to us. It is your choice which app you use and which one is available on your device:

GlassesOn
GlassesOn will provide you with everything you need to buy new glasses. The Google Play app developed by 6over6 measures your PD in less than a minute. The app has been approved by the FDA, CE and TGA.


To use GlassesOn to measure your PD you will need any standard magnetic strip card (e.g. a library card, rewards card or student card), light colored cards work best. Then, tap ‘Start PD’ on the app’s home page and follow the voice instructions. GlassesOn will do all the work for you. You will not require a ruler or mirror and there should be no manual adjustments required. 

Your measurement will meets the industry guidelines for accuracy (ANSI Z80.17) within 0.25D, PD within 2mm. However, 6over6 recommends that their technology should not be used as a substitute for an in-person visit to your eye doctor or any kind of eye exam. The parameters extracted from the scanned glasses are not a prescription.

EyeMeasure
EyeMeasure works in a similar way to GlassesOn. However, this app is recommended for iPhone users and is accessible to download from the online Apple app store.

EyeMeasure works by essentially turning your iPhoneX (or newer iPhone) into a 3D body scanner and measurement device. EyeMeasure allows you to measure the distance of your pupils from eye to eye. Then EyeMeasure segments your pupil height instantly both at the near and far distances. For this app you will not require any additional tools such as cards, mirrors, measuring tapes or pens. The app is extremely accurate [to up to 0.50mm] for the perfect prescription lenses. 

EyeMeasure can provide you with instant PD measurements and segment heights for near and far focal lengths. Whether you require single vision lenses, varifocal lenses, reading glasses or distance glasses - EyeMeasure will read and report your PD. 

Manual Measuring
We strongly recommend using either of these apps, however if these are not accessible to you then please call or email our office. The PRET A VOIR team will help you obtain your PD details by sending us a photo. 

For your photo, we will send you a set of instructions to follow so we can extract the most accurate pupil distance reading.

We suggest you ask a friend to help with this as ‘selfie’ style photographs or those taken in a mirror will not allow us to obtain an accurate measurement. The camera needs to be at least 10 feet [or 3 meters] away and level with your eyes. You can zoom in to get a better image but please ensure you have removed your glasses and you’re standing in a well lit area.

It is really important that the photograph is in focus and not blurry. Please ensure we can clearly see your eyes.

We will then ask you to hold a magnetic strip card, similar to the GlassesOn app, this can be a gift card, library card or credit card. This is used for scale. Please face the magnetic strip towards the camera and centered below your nose. 

Our team will then let you know your pupil distance (PD) and help you complete your order!

If you have any questions at all regarding your pupil distance or the process of measuring this please get in touch with our team. Our dispensing opticians are always on hand to help.

Au Revoir,
PRET A VOIR

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