Here are a few different ways to get your PD (pupillary distance):

  1. Do it yourself with our easy online video below
  2. Stop into a SEE store and we will measure it for you for free
  3. Call the store where you last purchased glasses (they should have your PD on file)
  4. Go to an optical store and get measured

Quick tip: Most PDs fall somewhere between 52-68, with the average being 60.

Check out our video.

How to read your prescription:


Sphere or SPH represents the strength of your prescription. If you are nearsighted or need glasses for distance, your prescription will usually have a “-“ before the number. If you are farsighted or need glasses for reading, you prescription will usually have a “+” before the number.


Cylinder or CYL represents the amount of astigmatism correction you have in your lenses. If you don’t have any cylinder or CYL correction in your prescription you may not need any astigmatism correction or the amount of astigmatism correction is so low that no correction is needed.

AXIS or X:

Axis sometimes represented by an “X,” and a following number, represents the rotation that is needed in conjunction to the Cylinder in order for an accurate astigmatism correction. Cylinder numbers and Axis numbers go hand in hand, if you have one of the two numbers you will have both on your prescription.


Addition or ADD represents the additional reading power or magnification power necessary to see up close. The ADD is used in bifocal and progressive lenses, which are offered in store. The ADD power can also be used in reading glasses depending on how the optometrist writes the prescription.

O.D. represents the right lens

O.S. represents the left lens