How to Measure Pupillary Distance (PD)

What is pupillary distance (PD)?

Pupillary distance (PD) refers to the space between the centers of your pupils. It helps ensure that prescription lenses are properly aligned in your glasses.

Why it's important?

The "optical center" of prescription lenses needs to line up with where your eyes focus through the lens. Pupillary distance is crucial for ensuring this alignment, making accuracy essential.

What is single and dual PD?

  • Single PD

    Single PD, or binocular PD, is the pupillary distance between the centers of your pupils.

    Range of Adult PD: 54-74

    Range of Child PD: 43-58

  • Dual PD

    Dual PD, or monocular PD, consists of 2 numbers and is the distance between the centers of each pupil to the bridge of the nose.

    Dual PD is usually written as 32/30. The first number refers to the right eye (OD), and the second number refers to the left eye (OS).

  • How do you calculate near PD for reading glasses?

    Subtract 3 mm from your distance PD.For example, if your distance PD is 63mm, then your near PD is 60mm.

    If you use dual PD to calculate near PD, then subtract 1.5mm from each eye’s measurement.For example, if your dual PD is 33/31mm then your near PD would be 31.5/29.5mm.

With your prescription and PD, pick now!