First, Your pupillary distance (P.D.) is the horizontal distance between your pupils, in millimeters. The Eye Butler expert who crafts your lenses needs this information in order to position the optical center of your glasses correctly. You may or may not have the PD values written on your Rx, as some offices might take this, but most will not. Note that your doctor is obligated by law to provide you with a copy of your Prescription, so long as it is still valid, but they have no obligation to take your PD. If your doctor/technician did take the value(s), and enter them on your Rx, they should be listed after the ADD section, or below all the Rx information. You may or may not have 2 numbers. For most Single Vision lenses, a single, combined value from one eye to the other is sufficient. For progressive lenses, a monocular PD, which is a separate value for each eye, is required. Eye Butler utilizes two ways to measure your PD, in the event your doctor doesn’t or will not provide the values. The first, is to click on the Take Your PD 
button on our site, which is located on the Rx entry page. Click on the Red button and a pop up will open to walk you through how to take your PD (see image below):
Watch the video associated witht the PD measurement tool, as it will walk you through the exact steps of how to take your pd.
We also recommend an interactive PD measurement app that you can download and utilize on the Apple app store at:
https://apps.apple.com/us/app/pd-easy-pupillary-distance/id1560353383
This application will allow you to take a monocular PD, which is useful for Progressive lenses, but the app requires newer IOS devices.
