To measure your pupillary distance (PD) accurately, follow these steps:
- Stand in front of a mirror with a ruler or PD measuring tool.
- Focus on your reflection and hold the ruler against your brow.
- Align the ruler’s zero point with the center of your left pupil.
- Have someone help you measure the distance to the center of your right pupil.
- This measurement is your PD, typically expressed in millimeters.