What Should I Know? What is pupillary distance? Pupillary distance, also known as “PD,” is the distance between your pupils, and the measurement that is necessary to ensure the correct positioning of your lenses within the frame you have chosen. Your PD is essential to making your glasses and important because it greatly affects the way you see comfortably through your lenses. How do I Obtain my PD? When you get your eye exam done, your eye care provider will typically measure your PD for you. When asking for a copy of your prescription, you can also ask for your PD. However, only a few states in the U. S.…