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What is Pupilary Distance (PD)?


What is pupil distance (or PD for short)?

It is the distance in millimeters from the center of the pupil of the right eye to the center of the pupil of the left eye. To give you optimum vision, this measurement must be accurate so that the center of the lens is in line with the center of your eye.

To get your pupil distance, you need to ask your optician for this measurement at the time of your eye test, measure it yourself with a mirror, or ask a friend to help you. If your optician measures your PD, make sure it is marked on your prescription.

                    
You can measure your own PD using a mirror and a millimeter ruler.

Place the ruler flat against your forehead and with your right eye closed, line up the zero on the ruler with the center of your left pupil. With your left eye closed, take a reading of the ruler at the center of your right pupil.                                         

If you have difficulty seeing what you are doing, then use a magnifying mirror. If it is easier, line up the outside of the iris of one eye with the inside of the iris of the other eye and use that measurement.