PUPILLARY DISTANCE (PD) measures 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. The average adult’s PD is between 54-74 mm; kids are between 43-58 mm.
If you do not have your PD, you can measure it yourself with the help of a friend, or you can measure it yourself with our step-by-step PD Measurement Ruler Form
SINGLE PD is the pupillary distance between the center of one pupil to the other, which can be a distance PD or near PD.
DUAL PD, or monocular PD, consists of two numbers and is the distance between the centers 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).
Every set of prescription lenses has an “optical center,” which is determined by pupillary distance. Pupillary distance is used to determine where you look through the lens of your glasses and should be as accurate as possible.