What is a PD Measurement?

What is a pupillary distance measurement?

When buying a pair of designer glasses with prescription lenses at VizioOptic.com, we require some important information in order to ensure your lenses provide the most precise vision possible. It is vital that you email or fax your prescription to us, but it’s even more important that this document includes your PD measurement.

The PD measurement is a figure denoting your pupillary distance. It is measured from the center of your left pupil over to the center of your right pupil. If this number does not appear on your prescription, you will have to visit your eye doctor to get an exact measurement, or you may check old prescriptions to see if it appears there (adult PD does not change).

We do not recommend trying to measure this yourself, as it can be quite difficult to get an accurate reading. If you absolutely cannot get to an eye health professional, have a friend help you out. Pupillary distance is measured in millimeters, and should be determined while you are looking straight ahead, focused on an object across the room.

If you have a dual PD listed on your prescription (32/33, for example), each number is the distance from your right and left pupil’s center to the center of your nose, respectively. We must emphasize that the right measurement is the number on the left, and vice versa, so try not to confuse the two.

Why is this number important? It is used to ensure that your lenses are perfectly customized to your eyes, as it pinpoints your exact optical center. Lenses are produced with a slight curve, rather than with a completely flat surface, so the PD measurement lets us know that your personal optical center is reflected exactly within the lens.

For more tips on how to buy glasses online at VizioOptic.com, please visit our guide to ordering lenses.

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