When ordering new glasses, one of the most important numbers on your prescription is PD – Pupillary Distance. This measurement ensures that the optical center of the lenses is perfectly aligned with your pupils, giving you clear vision without strain.

What is PD?

Pupillary Distance (PD) is the distance between the centers of your pupils, measured in millimeters. An optician uses this value to precisely position the lenses in your eyeglass frame.

How to Measure PD at Home

Method 1: With a Mirror

      1. Stand about 20 cm away from a mirror.

      2. Hold a ruler above your eyes, resting it against your forehead.

      3. Close your right eye and align the zero mark with the center of your left pupil.

      4. Open your right eye and read the millimeter line that matches the center of your right pupil.

      5. That number is your PD.

Method 2: With a Friend

      1. Look straight ahead.

      2. Ask your friend to hold a ruler across your eyes.

      3. They should measure the distance between the centers of both pupils.

      4. Write down the number in millimeters.

Single PD vs. Dual PD

• Single PD: one number for both eyes (e.g., 63 mm).

• Dual PD: two separate numbers for each eye (e.g., 31 mm / 32 mm).

Bonus Tip: If possible, ask your ophthalmologist or optometrist to include your PD directly on your prescription.

Measuring your pupillary distance is simple but essential for making accurate glasses. A correct PD means sharper vision, natural focus, and glasses that fit perfectly.