How to measure your PD

The 'PD' is the distance in mm from the centre of one pupil to the other. Also known as the 'Pupil Distance'.

This measurement is especially important for individuals who have high powered lenses in their glasses.

The 'PD' measurement is sometimes written on your prescription, which is given to you by your Optometrist at your eye exam. It can be given as one number together e.g. 61mm, or two numbers for each eye e.g. 30mm & 31mm (called Mono PD's). 

The measurement of your pupils can also be done easily at home, either on your own or with a friend. 

Please follow the simple steps down below to get a 'PD' measurement for your glasses:

Step 1

First get a small ruler in hand. 

If you are measuring your 'PD' on your own, then position yourself approximately ~20 to 25cm away from a mirror.

If you are using a friend, then give the ruler to them and position yourself arms length distance/~50cm away. It is preferable if you are both sitting when taking the measurement and also facing each other. 

Step 2

Gently place the ruler on your forehead and position the '0' above your right pupil. Keep the ruler horizontal at all times.

If you are with a partner, have them do this for you by facing them and positioning yourself parallel to their eye level.  

Step 3

While looking straight ahead, measure the distance from the centre of your right pupil to the center of your left pupil.

If you are using a mirror, you can shut your right eye (RE) for more accuracy and use your other eye to read the measurement directly in front of you. 

If you are with a partner, have your partner shut their left eye and use their other eye to take the measurement which is parallel in front of them.

As you can see from the example, the ruler reads: 63mm. This would be your 'PD measurement'