How to Read and Enter Your Eyeglass Prescription
While you don't need to completely understand how to read your eyeglass prescription to place an order on Discount Glasses, you'll need to know the basics in order to select and order the right lenses for your eyes. We've provided assistance with how to read and enter your prescription in the information below. If you don't have a copy of your prescription, or are not sure how to read it, rest assured that as long as you have your doctor's information we can contact your doctor directly in order to obtain your correct prescription.
How do I read my eyeglass prescription?
Your prescription should look somewhat similar to the following:
Below are examples of how a prescription can look and how it would be entered into our website.
Doctors write prescriptions in many different ways. Below is an explanation of how to tell if your prescription is for single vision or bifocal lenses.
Single Vision prescriptions are for patients who have trouble seeing either near or far (but not both). An example of a Single Vision prescription can be seen below. As you can see, the prescription has no value in the ADD column.
BIFOCAL / PROGRESSIVE VISION
Bifocal prescriptions are for patients who have trouble seeing both near and far. An example of a Bifocal prescription can be seen below. As you can see, the prescription has a value in the ADD column. You will only have an ADD measurement if you wear bifocal/progressives lenses.
ADD corrections are almost always the same number for both eyes. If you happen to see the letters PAL next to one of the numbers, or written elsewhere on your prescription, this means your doctor indicated that you will need a different ADD correction for progressive bifocals versus lined bifocals. Since Discount Glasses only offers Progressive Bifocal lenses, you'll want to use the number with PAL next to it when entering your prescription on our site. That number will apply to both eyes so make sure you enter it on both eyes. Below is an example of a PAL prescription:
What if my prescription has a value in the Prism column?
Unfortunately, Discount Glasses is not currently able to create glasses with Prism corrections. An example of a prescription with a Prism correction can be found below:
I want to purchase eyeglasses through Discount Glasses, but this prescription stuff is confusing. Is there an easier way?
Absolutely! You can always leave the prescription fields blank when ordering, and then either send us a copy of your prescription, or give us your eye doctor's contact information and we will collect your prescription information directly; ensuring that your prescription is correct while you remain free of worry!
Looking for more information about eyeglass prescriptions?
Eyeglass Prescription Glossary / Abbreviations
OD - This is shorthand for oculus dextraous which means Right Eye.
OS - This is shorthand for oculus sinister which really means Left Eye.
OU - This is shorthand for oculus uterque which really means Both Eyes. If you see this, you'll want to enter the prescription the same on both eyes.
Sphere or Power - SPH or PWR - This is the main strength of your eyeglass prescription, and is written in 0.25 increments. If the field has 'SPH', 'PL', 'PLANO', or '00', this means your there is a 0.00 power as should be entered as so. Discount Glasses can create lenses for prescriptions with Sphere ranges between -20.00 and +20.00.
Plano - PL - This indicates there is no spherical correction in this eye. A plano lens would have no focusing power or correction to it.
Balance - This indicates there is no vision correction in this eye. It's a non-prescription lens and is used when only one of your eyes requires vision correction
Cylinder - CYL - This indicates the amount of astigmatism, and is written in 0.25 increments. Not all prescriptions have a cylinder correction, and some prescriptions have a cylinder correction in only one eye. If you don't have an astigmatism correction then your doctor may leave this field blank, or they may put 'SPH', 'DS', 'Plano', or '00' in this field. This means you do not have an astigmatism correction in one or both eyes. Discount Glasses can create lenses for prescriptions with Cylinder ranges between -5.00 and +5.00. Positive (+) Cylinder values will be converted into negative (-). See our FAQ page for an explanation of why.
Axis - AX or X - This is also part of the astigmatism correction, and is written in increments of 1 (one). If there is no cylinder, then there should be no axis. Since it's a degree/angle, it will be represented as a value between 1 and 180. If there is no cylinder, it's possible that the doctor might enter 0, but this would just indicate that there is no axis. Discount Glasses can create lenses for prescriptions with ADD ranges between +0.25 and +3.00.
ADD - This is a value that is commonly used for bifocal or progressive lenses, as well as reading glasses. It indicates how much power gets added to the distance Rx to create the reading-only Rx; or as it applies to the glasses you'll order from Discount Glasses, it determines the correction strength for the bottom half of your bifocals progressive lenses. It is written in increments of 0.25. Discount Glasses can create lenses for prescriptions with ADD ranges between +0.25 and +3.00.
Prism or Base or Base Curve - A prism is used when both eyes are not properly aligned and they need a prism to re-align them. The Base is the rotation of the prism. These fields are rarely used, and the correction type is not currently offered on Discount Glasses eyeglasses. There are two separate parts to a Prism correction. The first part is the diopter strength (e.g. 2.0) and the second is the direction (e.g. BU). There are four different directions. Base-Up (BU), Base-Down (BD), Base-In (BI), and Base-Out (BO).
Pupilary Distance - PD - This is the distance in millimeters between your right pupil and left pupil. A more detailed explanation of Pupillary Distance can be found in our What is Pupillary Distance (PD)? page.
Segment Height or Seg Height - SH - This is the vertical measurement in millimeters from the bottom of the lens to the beginning of the progressive addition on a progressive lens, or the top line of a lined bifocal. Segment height does not apply to Single Vision lenses. You will need the frame to be able to measure segment height because you can only measure it while the glasses are on your head.
Near Vision or Near Vision Only - NV or NVO - This is written when your doctor is recommending reading-only glasses. (This is also known as farsighted)
Distance Vision or Distance Vision Only - DV or DVO - This is written when your doctor is recommending distance-only glasses. (This is also known as nearsighted)
Astigmatism - An optical condition that can cause blurry vision. This is corrected by a Cylinder and Axis correction on a prescription.
Binocular - A term used to describe the simultaneous use of both eyes at the same time.
Monocular - Refers to only one eye.
Oculus Dexter (OD) - Latin for right eye
Oculus Sinister (OS) - Latin for left eye
Oculus Uterque (OU) - Latin for both eyes
Progressive Additive Lens - PAL - The ADD value specifically for progressive lenses.
Still have questions? Call us at 1-888-264-5400 to speak to one of our trained Customer Service Representatives.