How To Read Your Prescrption

Learning how to read and understand your eye prescription is critical. The symbols, numbers and abbreviations you get after a vision test can help you determine whether you are farsighted, nearsighted or have astigmatism — and to what degree. Having an accurate prescription can help you choose effective eyeglasses to correct your vision and ensure comfort.

Whether on paper or digital, your eye prescriptionoften looks like a chart or gridwith rows, columns and cells. It will have a mix of abbreviations, positive and negative numbers and symbols. Knowing their meaning can help you make sense of your prescription and get the right eyeglasses for your vision needs.

Eye prescriptions include specific symptoms and abbreviations indicating the parameters of corrective lenses required for each eye. Common symbols include:

OD

Short for “oculus dexter," the Latin phrase means “right eye.”

OS

This stands for the Latin “oculus sinister,” meaning “left eye.”

OU

Short for “oculus uterque,” which means “both eyes.”

Sphere (SPH)

This abbreviation indicates the amount of power needed to correct nearsightedness or farsightedness.

Cylinder (CYL)

This specifies the amount of lens power to correct astigmatism, with the number indicating the degree of correction needed.

Axis

This indicates the orientation of the astigmatism correction, measured in degrees from one to 180.

Prism

If present, prism indicates the amount of power needed to correct eye alignment problems.

Base

The base refers to the direction of the base of the prism, typically noted as “in,” “out,” “up,” or “down.”

NV (N)

This abbreviation includes Near Vision, the power needed for near vision in multifocal prescriptions.

DV (D)

This letter represents Distance Vision or the power needed for distant vision in multifocal prescriptions.

Positive values

Positive values indicate hyperopia, or farsightedness.

Negative values

A minus sign indicates nearsightedness — or myopia.

Other Abbreviations Used in Eye Prescriptions
  • Intermediate (INT): For multifocal prescriptions, this abbreviation specifies the power needed for intermediate vision, typically computer use.

  • Pupillprescriptioary Distance (PD): The PD is the distance between the centers of your pupils. The number — measured in millimeters — ensures the optical centers of the lenses correctly align with your eyes to provide the most accurate vision possible.

  • Addition (ADD): This abbreviation denotes the additional magnifying power required for the reading portion of the lens in multifocal prescriptions like progressive or bifocal lenses.