PD is very important for accurately fitting your lenses to achieve vision acuity. Generally speaking, the average PD for adults is 55-70 mm and for kids is about 50-70 mm. A difference about 2-3 mm is allowable.
Checking with your doctor is recommended. You can also measure it this way.
Step 1: Stand with a friend facing you and place a millimeter ruler on the bridge of your nose. Keep the rule "0" measurement is exactly in line with the center of your left pupil. Hold the ruler straight.
Step 2: Let your friend read the measurement between the left pupil and the right pupil while you look straight ahead.
Step 3: For measuring a PD with high accuracy, please do it 3 times and take an average number of them as the final PD measurement.
For those requiring bifocal or progressive lenses, we strongly recommend you get this information from your optician to ensure the accuracy of your glasses.
You may also measure your PD in front of a mirror,here we show how to do it.