What's PD?

PD stands for Pupillary Distance. As the name suggests, it is the measurement in millimeters between your pupils. This measurement allows us to align your pupils accurately with your vision correction in the lenses we are mounting in your frames. When your pupils are lined up with the center of the power correction, your eyes will focus easily, comfortably, and with crystal clear clarity. However, if your lenses are not aligned with your pupils, it can cause eyestrain and discomfort as a result of your eye muscles having to work harder to adjust your focus.

How to measure your PD?

Measuring your Pupillary Distance (PD) is important for ensuring that your eyeglasses are properly aligned with your eyes, providing optimal vision and comfort. Here's how you can measure your PD at home:

Method 1: Using a Ruler and Mirror
  1. Get a millimeter ruler: You’ll need a ruler that measures in millimeters (mm) for accuracy.
  2. Stand in front of a mirror: Stand about 8 inches (20 cm) away from the mirror.
  3. Close your right eye and align the zero mark of the ruler with the center of your left pupil.
  4. Close your left eye and open your right eye: Look straight ahead, and note the measurement at the center of your right pupil. This number is your PD in millimeters.
  5. Repeat the measurement a few times: To ensure accuracy, measure a couple of times and take the average.
Method 2: With Help from a Friend
  1. Sit still and look straight ahead.
  2. Have a friend hold the millimeter ruler across your nose.
  3. Measure the distance between the centers of both pupils: Your friend should align the zero mark with the center of one pupil and then read the measurement at the center of the other pupil.

Method 3: Using a Digital PD App

Some apps and online tools can help you measure your PD using your smartphone camera. These apps usually guide you through taking a photo and then calculate your PD automatically.

Types of PD Measurements

  • Single PD: Measures the distance between the centers of your pupils and is used for single vision glasses.
  • Dual PD (Binocular PD): Involves two measurements: one for each eye. The distance from the center of your nose bridge to each pupil is recorded. This is useful for progressive lenses.

Typical PD Ranges

  • For adults, the average PD usually falls between 54 mm and 74 mm.
  • For children, it typically ranges from 43 mm to 58 mm.

Measuring your PD accurately is crucial for getting the right lens placement in your eyeglasses, so take your time with the measurement or seek help if needed.