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How to Read Your Contact Lens Prescription

Reading your contact lens prescription may seem confusing at first, so we’ve broken it down for you.

The meaning for each abbreviation:

  • OD: Oculus Dexter (Latin for right eye)
  • OS: Oculus Sinister (Latin for left eye)
  • PWR: Power (also referred to as Sphere or SPH)
  • BC: Base Curve (usually a number between 8 and 10)
    • If your brand only comes in one base curve, your prescription will not contain a BC value
    • Your BC might be different depending on the brand
  • DIA: Diameter (usually a number between 13 and 15)
  • Brand: The brand of contact lenses fitted for your eyes
Sample Rx
Toric Prescription

Toric Lenses for Astigmatism

Prescriptions to correct astigmatism contain two additional numbers that are indicated by the following abbreviations:

  • CYL: Cylinder (usually a number between -2.25 and -0.75)
  • AX: Axis (usually a number between 0 and 180)

Multifocal Lenses for Presbyopia

Multifocal lenses for presbyopia (in one or both eyes) prescriptions contain an additional indication of "high" "medium" or "low" with the following abbreviation:

  • ADD: Also known as "Add Power" or "Extra Strength"
Multifocal Prescription

Why Your Contact Lens Prescription is Important

You need a valid contact lens prescription before being able to purchase contacts. Doctors prescribe a contact lens that is perfectly fitted for your eye shape by measuring your eye surface during a contact lens exam.

Annual eye exams are still necessary to maintain overall eye health. Always consult with your eye care professional if you are having problems with the contact lenses they prescribed. Feel free to reach out to our Customer Service Team with any questions or concerns.

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