How to read an eyeglasses prescription

Read your Eyeglasses Prescription with Ease Sphere, Cylinder, Axis, oh my! We'll teach you what all this means so you can better understand the exact lenses you need to order with your EyeBuyDirect glasses.

Hi there. Does it worry you to order prescription glasses online when you are not really sure how to read your prescription? Well, worry no more. With just a few simple terms, you’ll be able to read any prescription. So, let’s get started.

The first terms you need to know are OD and OS. OD stands for 'right eye'. OS stands for 'left eye'. Some prescriptions just have a "R" and a “L”.

Next we have SPH which stands for spherical error. This number is basically how strong your lens needs to be to correct your vision. A "+" sign next means you are farsighted.  A "-" means you are nearsighted.

Now, if you have astigmatism, you’re going to see CYL and AXIS on your prescription. That stands for cylinder, and axis represent the astigmatism correction. Astigmatism is a visual condition where the eye is not completely spherical but is shaped more like a football. CYL is the degree at which your eye is shaped like a football and the AXIS represents where the vision is blurred from 1 to 180 degrees.

ADD is a term used with bifocal and progressive lenses. It stands for ‘additional,’ as in ‘additional strength here’ to help you focus on reading and close work.

And last we have PD, which stands for Pupillary Distance. This is the distance between the center of one pupil to the other. Now, if your prescription does not have PD on it, don’t worry. We have a tutorial that tells you how to measure this yourself.

So now know everything you need to read a prescription. Go forth and impress your friends and family with your newfound technical knowledge. Bye!

Your glasses prescription is a series of numbers, usually in a chart, that describe the lenses needed to correct your vision. This chart has two rows, one for your right eye and one for your left. Four columns are used to precisely describe your correction.

Watch our prescription video guide

Understanding your prescription

How to read a prescription

Let's translate the abbreviations.

SPH or Sphere

SPH or Sphere

Refers to the amount of spherical error for your eyes, measured in quarters and proceeded by a (+) or (-).

CYL or Cylinder

CYL or Cylinder

Describes astigmatism, a refractive error that causes distorted and blurred vision, measured in quarters and proceeded by a (+) or (-).

AXIS

AXIS

Indicates the orientation of astigmatism, measured in degrees 1 to 180.

ADD or NV

ADD or NV

Meaning Near Vision is used for multifocal or reading correction, measured in quarters. This power for bifocal or progressive lenses enlarges immediate vision and is therefore always indicated by a positive sign (+).

O.D.

O.D.

Refers to the right eye.

O.S.

O.S.

Refers to the left eye.

PD or Pupillary Distance

PD or Pupillary Distance

Refers to the distance in millimeters between the center of one pupil to the center of the other.

Enter your prescription

 
Sphere (SPH) ?
Cylinder (CYL)?
Axis?
Addition (near) ADD?
Right Eye (OD)
Left Eye (OS)
  • Pupillary Distance (PD):?  
  • Save this prescription as:
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