Lens strength needed to correct your vision. Negative (-) means nearsighted, Positive (+) means farsighted.

The degree of astigmatism in your eyes, as well as an axis number that indicates the orientation of the astigmatism.

ADD stands for the additional correction that you need for reading. It is used for multifocal lenses and readers.

Prism is used to correct diplopia (double vision). A prism bends light to align your vision so only a single image is seen.

Vertical prism correction is for vertical eye misalignments and prescribed upwards in one eye and downwards in the other.

Horizontal prism correction is for lateral eye misalignments and prescribed in the same direction for both eyes.

The distance between your pupils. An average PD measurement is 63mm, but it varies by person. Select 63mm if unsure and the store can follow up if needed.