How to Measure Your Pupillary Distance

Pupillary Distance (PD)

Your Pupillary Distance, sometimes referred to as ‘PD’ is the horizontal distance between the centres of your pupils in millimetres. It is needed to ensure the centre of each lens is aligned with the centre of your pupils.

Note: This is generally not included on your prescription. Either 

• Ask your optician for your PD measurement. It is usually written as one measurement such as 60 (60mm) but can also be shown as R 29 L 31. When written like this it is the individual distance from you right and left pupils to the centre of your nose. 
• Measure the distance yourself using a mirror and a ruler as explained below.  
  Use an average PD measurement which is about 62mm for women and 64mm for men. This will not be a problem for most people who either are the average or have weak prescriptions (-2 to +2 spheres). For people with stronger prescriptions it would be better to measure your PD. Though the spectacles will not harm the eyes, they could cause discomfort and eye strain. Alternatively,
• Send us an old pair of your glasses and we will match the centres to these. We will return the glasses with your new pair. Please include a note with your name, telephone number and your reference number that will be provided on the completion of your purchase.

How to measure your PD

Asking a friend to help you using a ruler

This is the easiest method for measuring you PD. Please follow the guide below:

1. With your friend sitting opposite you at the same height, ask them to place a ruler across your forehead just above your eyes with the millimetre side facing upwards.
2. Ask your friend to close their right eye and you then look directly into their left eye. Ask your friend to slide the ruler so that the zero value is in the centre of your right pupil and to keep the ruler very steady across your forehead.
3. Ask your friend to close their left eye and for you to look directly into their right eye. Your friend will then read off the measurement to the centre of your left pupil.

That is all there is to it. Please see the diagram above to help you further.

Asking a friend to help you using your current glasses

1. Put your glasses on so that they are comfortable and steady. Ask your friend to stand opposite you and mark on your lenses the position of your pupils with a non-permanent marker.
2. You will now have two lines directly in front of you whilst wearing your spectacles. Take off your glasses and measure the distance between the two markings. If you have a reading of 6cm then type in our prescription page a PD distance of 60. If the measurement is 6.4cm then your PD will be 64.