How to measure your PD (Pupillary Distance)
An accurate PD measurement is needed when ordering glasses. An accurate PD provides both clear and comfortable vision. This measurement tells the lab where to properly align your eyes with the optical center of the lenses. The pupils need to aligned with the optical center of the glasses otherwise you can have headaches and unwanted eyestrain.
How to find your PD
1. Position your self directly in front of a mirror, holding a ruler at above arm's length.
2. Close your right eye and look at your left eye.
3. Set the "0" mark (in mm) of the ruler on the left pupil center.
4. Open your right eye and close your left.
5. Read the ruler marking at the point that corresponds to the center of your right pupil.