How to read your eye prescription?



What Are The Terms On Your Eyeglass Prescription?

O.D. stands for oculus dexter, meaning right eye.

O.S. stands for oculus sinister, meaning left eye.

SPH (or Sphere) indicates the strength of your lens, or how strong your lenses need to correct your nearsightedness or farsightedness.

CYL (or Cylinder) indicates the amount of lens power for astigmatism, it also tells the lens strength needed to fix astigmatism. Leave this column blank if nothing is written on your prescription

AXIS describes the degree and direction of your astigmatism. It’s applicable only if you have CYL power

Axis ranges from 0 to 180 Degrees & is always present along with Cylinder Value

ADD or NV This provides magnifying power for reading, progressive and bifocal lenses. You will have the same number for both eyes. ADD is only needed for magnifying power of reading, progressive and bifocal lenses.

Pupillary distance (PD)  is the distance between the pupils of your eyes. Knowing your PD is important for you to purchase glasses with Bifocal or Progressive glasses(usually required for people above 40 years in age), however PD is not required for Single Vision powers.

  • Ranges from 50 to 74 mm