Pupillary Distance (PD): What It Is and How to Measure It
What is pupillary distance (PD)?
Pupillary distance (PD) is the distance, in millimetres, between the centres of your pupils. We use it to centre your lenses correctly in your frames, so your eyes look through the right part of the lens. It matters most for stronger prescriptions.
How to measure your PD at home
- Stand about 20 cm (8 inches) from a mirror, or ask a friend to help.
- Hold a millimetre ruler just below your eyes, level with your pupils.
- Looking straight ahead, close your right eye and line the 0 mm mark up with the centre of your left pupil.
- Close your left eye and read the measurement across to the centre of your right pupil. That number is your PD in millimetres.
If your prescription already includes your PD, simply use that number. Some prescriptions list two numbers (for example 31.5 / 32.5); these are separate measurements for each eye, and you can send them to us as they are.
Sending us your PD
Enter your PD in the box on the product page when you order. If you are unsure, message us on WhatsApp at 07951 420658 with your prescription photo and we will help before your lenses are made.