Measuring your Pupillary Distance (PD)
Note to varifocal wearers: After ordering, we will send you a PD ruler and some brief instructions on what to do...
Your Pupillary Distance (PD) is the distance between the centre of one pupil to the centre of the other pupil (the blacks of your eyes) measured in millimetres.
This measurement is an important piece of information that we need to deliver the very best vision in your new glasses.
Your PD is usually written as one value (e.g. 66mm) but sometimes written as 33/33 if you are symmetrical or 34/32 if one eye is slightly further away from the centre of the nose than the other, which is very common.
The average PD measurements for women is 62mm and for men 64mm. Between 58 and 68 is quite normal though.
We do encourage you to ask your optician for your PD measurement. If your optician is reluctant to give you this, you’ll be pleased to hear that it is easy enough to measure your PD using a simple ruler and the help of a friend.
Here is how you can measure your pupillary distance:
How to Measure Your Pupillary Distance:
Pupillary distance can be easily measured looking in a mirror and using a ruler! Please follow these steps:
- Stand in front of a mirror at a distance of about 20cm (8 inches)
- Close your right eye
- Place your ruler flat against the mirror and align it horizontally with the millimetre scale pointing upwards
- Looking over the top of the ruler with your left eye, align the zero mark of the ruler in the centre of your left pupil
- Now open your right eye and close your left but keep your head still and the ruler in the same position
- Read the millimetre measurement corresponding to the centre of your right pupil
- To be sure, you can repeat this process a few times for consistency
Make sure your friend is sat at roughly the same height as you and ask them to place a ruler across the bridge of your nose upside down so that the millimetre measurements are on the edge of the ruler closest to your eyes.
The measurer holds the ruler in their left hand across the bridge of your nose and closes their LEFT eye to avoid any parallax error. With their RIGHT eye open, they line up the ruler with the center of your left pupil. Then, without moving the ruler, they close their RIGHT eye and with their LEFT eye open, read the measurement to the center of the RIGHT pupil.
Best results are achieved if you fix your gaze on the bridge of the nose of the person taking the measurement. This point should ideally be around 16 inches or 40 cms away.
It can be difficult to decide where the centre of the pupil is, so you may prefer to measure from the far left edge of the Iris (coloured part of the eye) of one eye to the far left edge of the Iris of the other eye. See diagram below. This will give us the same measurement than if we had gone for the pupil centres.
Follow these steps:
- Put your glasses on
- Ask your helper to stand in front of you and mark a dot on your glasses directly above your pupils left and right (Please be sure to use a NON-PERMANENT MARKER PEN)
- With a ruler, measure the distance between the 2 dots
We can send you a custom-made PD ruler to help you measure your PD if this is helpful.
- If you have a mono pd ruler (see below) you can be a little more accurate.
- Place the mono pd ruler over the bridge of the nose.
- Use the technique as above to measure the distance, either pupil centre to pupil centre or to the edge of each Iris (always ensuring you go from left edge to left edge).
You should now have two numbers that when combined will give your total PD, ie R = 33mm | L = 31mm will give a total PD of 64mm.