A typical prescription usually looks like this:

Or like this:

R -3.25 / -1.00 x 176

L -3.50 / -1.25 x 180

What do these letters mean?

1. O.D. = Right Eye

2. O.S. = Left Eye

3. SPH (Sphere) = This refers to the power of correction needed to improve nearsightedness or farsightedness. The higher the number, the stronger the correction required.

4. (-) = Nearsightedness (difficulty seeing far away)

5. (+) = Farsightedness (difficulty seeing both near and far)

6. ∞, PL, or Plano = No correction needed

7. CYL (Cylinder) = Astigmatism correction. If blank or marked with DS/SPH, you don’t have astigmatism.

8. AXIS = Position of the astigmatism, between 1 and 180 degrees. This is always present if CYL is filled in.

9. ADD (Addition) = Additional lens power needed to make it easier for you to read. This number is seen on prescriptions for reading glasses or the lower portion of progressive lenses. 

10. PRISM = Special correction for specific conditions (usually double vision). Prescriptions with prism must be placed in-store.

IMPORTANT to check that your prescription:

- Is issued by a licensed optometrist.

- Has not expired (see our article 'Prescription Validity by Province').

- Is intended for glasses (not contact lenses).