How to measure your PD?

What’s PD?


PD is short for pupillary distance. Pupillary distance (PD) or interpupillary distance (IPD) is the distance measured in millimeters between the centers of the pupils of the eyes.This measurement is required to correctly position your prescription lenses. Pupil distance can be expressed in two ways. Binocular PD is the total distance between your pupils. Monocular PD is the distance from the bridge of your nose to your pupil on each side. A monocular PD measurement will be two numbers.

We recommend that you ask your eye care professional for your PD measurement or measure pupil distance at home. (We highly recommend checking your PD with your doctor, especially for bifocal or progressive lenses)

NOTE: you may receive two PD numbers that are off by a value of 3mm (such as 69/65). This means that your pupil distance for distance vision (or DPD) is 69. And the smaller value is used only for ordering reading glasses.If your most recent eye exam did not include the PD value, but a previous one did, you can use the previous value.

How to measure PD at home?


Find a millimeter ruler for measurements and a mirror or a friend.


Measure your own PD

  • Step1: Stand 20cm (8inches) away from the mirror, hold the ruler over your eyes and keep it horizontal.

  • Step 2: Close your right eye and keep the ruler's "0" measurement exactly in line with the center of your left pupil.

  • Step 3:While looking straight, Close your left eyeand open your right eye .

  • Step 4:Read the mm line that lines up the center of your right eye, the number is your PD measurement.

A friend help to measure your PD

If you friend is helping you measure your PD, you will need to keep both of your eyes open and have your other friend put the zero on the millimeter ruler over the center of one pupil, and then measure the distance to the center of the other pupil.

NOTE:keeping your eyes as still as possible. Look above his/her head at something approximately 10-20 ft. away. Do not look at the measuring person!