PD or Pupillary Distance measures the distance between the centers of your pupils and is used to center a prescription lens accurately in your frames. The distance is measured in millimeters between the centers of each pupil. Your eye doctor might use PD to check parts of your vision or eye function, but it's not usually important for managing your vision treatment. That's why it may not be included with your prescription even though you need it when you're ordering glasses. What can you do?
