What Is My Pupillary Distance?
Your Pupillary Distance is the distance between the centre of one pupil to the centre of the other pupil (the blacks of your eyes) measured in millimetres.
It 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.
We do encourage you to ask your optician for your PD measurement, however, if you do not have PD on your prescription (most do not as opticians are most reluctant to offer this) - do not worry as it can be easily checked.
If you have not obtained your PD from your optician, we can still make your glasses using an average pupillary distance measurement based on your gender, the size of the frames, and the experience of our dispensing optician.
In most cases, this method is effective, but to avoid discomfort, if you have a particularly strong prescription or suspect that you differ from the average measurement, we recommend you measure your PD using the following methods.
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
We can send you a custom-made PD ruler to help you measure your PD if this is helpful.
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.
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