How to Measure Pupillary Distance (PD)

1. What is Pupillary Distance?


Pupillary distance (PD) is the distance between the centers of your pupils. This measurement is used to determine where you look through the lens of your glasses and should be as accurate as possible. 




2. How to Measure Your PD?


Your eye doctor will usually measure your PD during an eye exam. However, if it was not given to you, here will tell you how to measure it yourself.


1. Stand 8 in. away from a mirror.

2. Hold a ruler against your brow.
3. Close your right eye then align the ruler’s 0 mm with the center of your left pupil.

4. Look straight then close your left eye and open your right eye.
5. The mm line that lines up to the center of your right pupil is your PD.


More details you should know: 

1) Measure your PD 3–4 times to ensure it's accurate and consistent.

2) The adult's average PD is 54-74mm; Kid's is 43-58 mm. 


3. About Dual PD

Dual PD, or monocular PD, is the distance between the centers of each pupil to the bridge of the nose. Dual PD consists of two numbers and 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).