How Do I Obtain My PD Measurement?

What is meant by PD or Pupillary Distance?

This is the distance between your pupils, measured in mm. 

What is it used for?

This measurement is used in the preparation of your prescription spectacle lenses to ensure their correct placement in front of your eyes.

There are two types of PD:

Distance PD: Required for single vision distance, bifocal or multifocal glasses.

Near PD: Required for single vision reading and single vision computer (also known as intermediate) glasses.

How can I obtain my PD?

Method 1 – Refer to your prescription (The Easiest Way):

This is usually shown on your prescription from your Optometrist.  If you need help interpreting your prescription, simply send it to us and our Optometrists will happily decipher it for you <click here>.

Method 2 – Measure it yourself:

Measuring Distance PD

You will need the help of a friend and a ruler.  Sit directly facing each other at an arm’s length distance apart.

Ask your friend to keep her left eye closed while you look into her right eye/open eye.  While doing this, ask your friend to hold a normal mm ruler firmly against your forehead, lining up its “zero” with the centre of your left pupil.  Make sure you continue to look into her open eye while the ruler is being aligned. 

Next, without repositioning the ruler, ask your friend to close her right eye and to open her left so you look into this open eye.  While maintaining this eye contact, ask your friend to take note of where the centre of your right pupil meets the ruler’s scale.  This is your Distance PD measurement.  Repeat measuring a few times until you are confident with your measurement.

Measuring Near PD

Almost identical to measuring your Distance PD except the person being measured (i.e. you) will hold up and look at a pen 30cm directly in front of you the whole time while being measured.  Meanwhile, your friend doing the measurement will first have to close her left eye while pressing a ruler firmly against your forehead and line up its “zero” with the centre of your left pupil.  Next, without repositioning the ruler, ask her to close her right eye and open her left to read off where the centre of your right pupil line up with the ruler’s scale.  This is your Near PD measurement.  Repeat measuring a few times until you are confident with your measurement.

Note: As a general guide, your Near PD is around 3mm less than your Distance PD.

Method 3 – Get it from an old pair of glasses:

Take your old glasses to your Optometrist and he would be able to determine it for you.