Pupil distance (PD) is the distance (measured in mm) between the pupils of your eyes when looking far away in the distance. When prescription lenses are cut for the frame you have selected, our edging computers are programmed with your pupil distance so that the exact centers of the lenses are directly in front of your pupils.

Why is this measurement important? If the prescription lenses are not set at the same distance as the distance between your eyes, then an unwanted prism is induced which may cause eyestrain. In lower prescriptions, the amount of prism induced will be of no consequence and will not cause eyestrain. For prescriptions over (+) or (-) 2.00, knowing your P.D. is important.

How do I get my P.D. measured?

- Ask your eye doctor to take the measurement at the time of your eye examination.
- Call the last place that made your glasses for you and they should be able to tell you what it is.
- Go into any Optical facility and ask them to measure it for you. It will take only seconds to do and they shouldn’t charge you for it.

Monocular or Binocular? Pupil distance can be measured in one of two ways:

The first is monocular measurement, which will result in values somewhere between 26-36 mm.

The second type is a binocular measurement, in which case the number will typically be somewhere between 54-72mm. A binocular measurement is the exact total distance between your eyes, but if your face is not perfectly symmetrical, then this number may not be split equally between both of your eyes.

What if my P.D. is written 66/63? The first number is the P.D. number we require to make your lenses. The second number (63) is the near pupil distance. This number is only needed when reading glasses are required.