How to read an eye prescription

Figuring out how to read your eye prescription can be a real challenge and may feel like you're reading a different language. All those letters and numbers have important meanings when it comes to your eyewear, so we’re here to help.

Eye prescription terms & abbreviations

Your glasses or contact lens prescription may be digital or on paper. Either way, it will contain a chart that lists numbers, abbreviations, and sometimes words to define your eye prescription. Here are common eye prescription abbreviations and what they mean:

OD (Oculus Dextrus):

Refers to your right eye, is always listed before your left eye.

OS (Oculus Sinister)

Refers to your left eye. 

OU (Oculus Uterque)

Refers to both your eyes.

D (Diopter)

This is represented by a number on your eye prescription that shows how much focusing power is needed to correct your vision.

Pupillary Distance

This number is the distance between your pupils, which is important for ensuring the center of each prescription lens aligns with the center of each pupil.

- (Minus Sign)

A negative sign in front of the diopter number means you’re nearsighted.

+ (Plus Sign)

A plus sign in front of the diopter number means you’re farsighted.

DV (Distance Vision)

Another way to note farsightedness.

NV (Near Vision)

Another way to note nearsightedness. 

Glasses prescription terms

Your glasses prescription will appear like a small chart with columns and rows. The rows indicate which eye (right or left) the prescription is for, and the columns indicate the following:

 


Glasses

Power (PWR) or Sphere (SPH)

This shows whether you’re far (+) or nearsighted (-) and how much correction your eyes require.

Cylinder (CYL)

CYL represents the added correction for astigmatism and is usually a value between -2.25 and -0.75. Astigmatism is a common imperfection that’s found on the eye’s surface or inside your eye, which causes blurry vision.

Axis

This describes the position of the astigmatism in the eyes. Axis numbers are represented by degrees ranging from 1 to 180 on your eye prescription.

Addition (ADD)

This describes the additional magnifying power required to correct presbyopia (a common condition of aging eyes) and is usually prescribed to those needing multifocal types of lenses. The number is typically the same for both eyes and is always a positive number.

Prism

This is a rare term used to prescribe prismatic power for those with eye alignment problems. Prismatic power is used to help correct diplopia, or double vision. The prism bends light to help align the vision so only a single image is seen.

Contact lens prescription terms

If you receive a contact lens prescription, there are additional terms and abbreviations to help with eye prescription meaning:

Power (PWR) or Sphere (SPH)

On a contact lens prescription, you may see the SPH written as Power, which is the strength of your prescription. These terms are interchangeable. This shows whether you’re far (-) or nearsighted (+) and how much correction your eyes require.

Base Curve (BC)

The base curve, which is usually a number between 8 and 10, measures the curve of the lens and helps determine how comfortable the contacts are.

Diameter (DIA)

The diameter indicates the width that best fits your eye and is usually a number between  13 and 15.

Brand

Your contact lens prescription must include the brand of contacts being prescribed as there are different parameters set by individual manufacturers.

You have a right to your eye prescription

 

Your eye care provider is required by law to provide you with a copy of your prescription after your eye exam. For contact lens prescriptions, you will receive the prescription after the fitting. The provider can’t make you pay additional fees for the prescription, obligate you to purchase from them, or make your sign a waiver. Some states may allow eye care providers to charge fees for certain tests or contact lens fittings; however, that does NOT prevent them from giving you a prescription BEFORE you choose to purchase glasses or contacts.

Renew or fill your eye prescription with Pearle Vision

Knowing how to read an eye prescription empowers you to better understand your eyes and communicate with your provider about your needs.
Here at Pearle Vision, we are here to support you on your journey toward optimal eye health.

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