Your PD is not included possibly because it isn't part of the prescription usually. Sometimes the optometrist will write it on there , but the law doesn't require it .If you want to measure your PD by yourself ,you can do it with a mirror .First, put a ruler on the bridge of the nose using one hand when you are looking the mirror. make sure to keep your head and eyes still during the process . Second,with your right eye closed ,keep the rule "0" measurement exactly in line with the center of your left eyes pupil . Then open your right eye,and read the number that lines up with the centre of the pupil of the right eye. The number shows your PD.In case of error , you'd better repeat it for several times and get an average value .
You'd better ask your eye doctor who give you eye exam. If you don't want to visit him/her, you can also measure your PD under the help of your friends or families. Here are some tips maybe help for you to measure PD.
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, You'd better get this information directly from your optician.