How To Measure Your PD How To Measure Your PD What is Pupillary Distance Pupillary distance (PD) measures the space between the pupils of your eyes Why is it important It ensures that you are looking through the optical center of the lenses How to Measure Just look straight, and use a ruler to measure It’s better to ask your family or friend to help to measure. Please measure several times to get a more accurate value. how to measure pd As a reference: Normal PD range for adult: 58 – 68 mm Normal PD range for kids: 42 – 52 mm