Measure your Pupillary Distance (PD)
Your Pupillary Distance (PD) is the distance between the centres of your pupils, measured in millimetres. Knowing this number means we can make sure you’re always looking through the correct part of the lens — we can’t make your glasses until we’ve got your unique PD.
How to get yours?
If visiting a store, our retail assistants will measure your PD in just a few seconds. But if you’re buying glasses online and don’t already know your PD, you can use our online PD ruler to measure your PD yourself — it’s super easy!
Order your new glasses on our website and leave the PD section blank. Once we’ve received your order, we’ll send you an email with a link to our online measurement tool.
Get your laptop or phone camera ready, as well as a card with a magnetic strip, and follow the simple instructions.
Why is it important to measure your PD?
If your PD isn’t right, it can cause eye strain, fatigue, or simply not being able to see properly. The higher your prescription, the bigger the effect an incorrect PD can have. So get measuring!
Don’t forget: if something doesn’t feel right, you can always contact us for corrections.
If you need the help of our online PD tool, just leave the Pupillary Distance fields blank when entering your prescription during the checkout process. Then sit tight for our follow-up email.
Rest your phone or computer on a steady surface in a well-lit room.
Turn up the volume so that you can hear the instructions.
Look directly into the camera, not at yourself, despite the temptation.
If you wear glasses, take them off.
Grab your bank card (or anything with a magnetic strip). Light coloured cards work best.
Start the scan — make sure you’ve allowed access to your camera.
Hold the bank card by its top corner and press it flat on your forehead. We might ask you to make small adjustments — just go with it.
After the scan, you’ll have your PD. We’ll automatically add it to your completed order.
Whilst the distance between your pupils is one length, you’ll have to halve it to work out the PD for each eye, e.g. if your PD is 60mm, your left and right eyes will be 30mm each. If you can’t halve your PD to a round number, no problem - split them to the closest 0.5mm, e.g. if your PD is 60.5mm, fill in: right = 30mm, left = 30.5mm. We see this quite a bit so, don’t worry, we know how to deal with it.
The average PD is somewhere between 58-68mm. If yours falls outside this, or you have a prescription over +/-6 SPH, get in touch with us, and we’ll give you a helping hand. Visiting one of our stores? Easy, our retail assistants will measure your PD for you.