How to Take Pupil Distance Measurements (PD)

Your pupillary distance (PD) is the measurement between the centers of your pupils, and it's crucial for properly positioned lenses. While the most accurate measurement comes from your eye care professional using specialized equipment, there are several ways to measure your PD at home. The simplest method involves standing 8 inches from a mirror while holding a millimeter ruler horizontally across your brow. Close your right eye and align the ruler's 0mm mark with the center of your left pupil, then open both eyes and read the measurement at the center of your right pupil. For greater accuracy, repeat this process three times and calculate the average. Alternatively, you can ask a friend to measure while you look straight ahead at a distant object, or use your previous glasses with a millimeter ruler to measure the distance between the optical centers. Several smartphone apps can also help measure your PD, including:

• EyeMeasure (iOS)
• GlassesOn (iOS/Android)
• Pupil Distance PD Meter (Android) However, for the most precise measurement, we always recommend visiting your optician who can measure your PD using professional equipment, especially for progressive or high-prescription lenses where accuracy is crucial.

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