Guides
PD Measurement
PD helps us position the optical centre of your lenses correctly.
What is PD?
PD (pupillary distance) measures the distance between your pupils and helps us position the optical centre of your lenses correctly.
Binocular PD
62 mm
The total distance between your pupils, for example 62 mm.
Monocular PD
R 31 / L 31
The distance from each pupil to the centre of your nose, for example R 31 / L 31.
Where can I find my PD?
- Your eyewear prescription
- Previous optical records or receipts
- Your previous optician
- Existing eyewear documentation
- Home measurement (see below)
How to measure PD at home
Stand or sit facing a mirror, about 30 cm away, with your glasses off.
Hold a millimetre ruler against your forehead, resting on your cheekbones, with the zero mark aligned with the centre of one pupil.
Looking straight ahead, read the measurement to the centre of your other pupil. This is your binocular PD.
For monocular PD, measure from the centre of each pupil to the centre of your nose.
Repeat the measurement two or three times and use the most common result.
Printable PD ruler
Download and print our EYE POWER PD ruler on A4 paper at 100% scale (no fit-to-page), then use it for the steps above.
Download PD ruler (PDF)Home measurement can be useful, but accurate measurements are important for prescription eyewear. If you are unsure, contact EYE POWER before ordering.
Some progressive and specialised lenses require more detailed fitting measurements. If these are needed for your order, we will tell you before production.