Before you place an online order for eyeglasses, you need to know your pupillary distance (PD). This measurement—which is the distance between the pupils of your eyes—is needed to correctly center the lenses within the frame.
Although your PD is often measured by your eye doctor during your exam, PD measurements are not always listed on your prescription—but, no worries, it's easy enough to obtain using a ruler and a mirror.
- Hold a ruler against your brow
- Align the ruler's 0 mm mark with the center of the left pupil
- The millimeter line that aligns with the center of the right pupil is the PD
Adults generally have a PD within 54-68 mm, while children have a PD within 41-55 mm.
Please note that these instructions are for getting your Distance PD measurement. If you require prescription bifocal glasses then you will also need your Near PD, which is calculated by subtracting 3mm from this Distance PD measurement.