On the home screen of your PDCheck app you will see three different numbers like so:
PD: Short for Pupillary distance. This is the distance, measured in millimeters, between the center of your pupils. This value is required for anyone to order glasses.
Distance PD: Also known as Dual PD, this is the combined value of the distance from the center of your left pupil to the center of your right pupil. This is the most common requested value by most manufacturers of glasses.
Single PD (Left and Right): These values are the distance from one pupil (either left or right) to the center of your face. You can either use this value or the dual value when ordering glasses. We suggest you use these values if there is a large gap between your left PD and right PD.
Near PD: This is PD value is what you would use for ordering either reading, progressive or bifocal glasses. When ordering these style of glasses, you must put this value in the appropriate field.