PD Measurement
If you have a sphere or a cyl' value greater then 2.0 we recommend including your PD in the prescription form. If it isn't on the copy of your prescription you received don't worry, measuring your PD is a simple procedure - all you need is a friend and a ruler.

Make sure you're looking straight ahead (try and focus on a point in the distance behind your friend) then get them to measure the distance from the left edge of one pupil to the left edge of the other.

 

 

That's all there is to it - the PD in the above example is 56mm.