PD is the distance between your pupils, which is required to center your prescription in your frames. 

Sometimes optometrists do not measure PD unless you purchase glasses from them. You can always call your optometrist to get this number.  If you are unable to get it from your provider you can measure it yourself using one of the following methods:

Use a phone app to measure your PD (easiest)

Glasses On makes a mobile app for iOS and Android devices.  Just download the app and follow the instructions to measure your PD.

Use a ruler to measure your PD

  1. Grab a dry erase marker and your glasses
  2. While wearing your glasses, look at an object about 20 feet away
  3. Have your friend dot each lens directly over your pupil
  4. Remove your glasses
  5. Measure the distance between the 2 markings with a millimeter ruler for the total PD.  Your total PD measurement in millimeters (ie: 63.5)

Use an online web app to measure your PD

You can use your webcam or phone camera to measure your pd.  The company Vision Works has an online tool you can use to measure.  Check it out here: