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How to Measure Your Pupillary Distance (PD)

Pupillary distance, or PD, is the distance between the center of one pupil to the center of the other in millimeters. This measurement is important as it makes sure you are looking through the ideal place in your lenses. You need this number when you are uploading your picture for our Tryon function, as well you need it when entering your prescription. This number is usually stated on your prescription, but if not, follow the simple steps below to measure it yourself!

1. Find a standard ruler.

2. Position the ruler right over the center of your right pupil making sure the ruler is horizontal. Place the ruler against your forehead for more stability. You can stand in front of a mirror or ask someone to measure for you.

3. Keeping your head straight and looking straight head, measure the distance from the center of your right pupil to the center of your left pupil.

4. Repeat step 3 a few times for accuracy and average these measurements to arrive at your final PD measurement.

Another option is to download a free app, for example called GlassesOn, available for both iOS and Android devices. This app measures PD for you using computer vision.