What is a pupillary
distance (PD) measurement?

You can use one of the following methods to measure your PD at home. 

Using the Opthy app      

By yourself with a card

Yes, you can measure your PD with your phone using apps specifically designed for this purpose. The Opthy app guides you through the process and use the phone’s camera to capture the measurement. 

Your PD is not included on your prescriptions as it is calculated when you order glasses. Some opticians may charge for measuring your PD.

You can find your PD for glasses in a number of ways.

• Using a PD tool online or via an app. 
• Taking a photo using a loyalty card as demonstrated in the content above or measuring with a ruler.
• Visiting your local optician.

Accurate PD is important for lens alignment, as it may cause eye strain or fatigue.  Some online retailers might estimate your PD based on your frame selection and face size. We recommend providing an exact measurement using the Opthy app or measuring with a loyalty card as above.

Single / Combined PD measurement, is the distance between the centre of one pupil to the centre of the other.

Dual/ Seperate eye PD meaurements (Left & Right ), consists of two numbers and is the distance between the centre of each pupil to the bridge of the nose.

Dual PD is usually written in the following notation: 32/30. The first number is always the right eye (OD) measurement, and the second number is the left eye (OS).

You can measure your PD yourself using a rule following the steps below. For ease and convenience use the Opthy app or the loyalty card process to avoid errors.

Key steps:

• Stand up with your head straight, and an arm’s length away from a mirror.
• Hold a ruler against your eyebrows.
• Close your right eye and line up the ruler’s 0mm with the centre of your left pupil.
• Look straight ahead, and then close your left eye and open your right eye.
• The measured mm marking that lines up with the centre of your right pupil is your PD measurement. If you use your glasses for distance vision, this will be your PD.
• Halve this number and enter into the PD field for each eye.