How To Read Your Eyeglass Prescription

Thu, January 27th, 2022

Understanding your eyeglass prescription shouldn't be rocket science and most certainly shouldn't require you to know Latin. Yet, there you are, confused as to what all the abbreviations, acronyms, and numbers mean on your script. 

No need to worry; Hubble's come to the rescue! 

Get ready to understand precisely what your prescription says and what it all means for your vision. 

The trick to comprehending your glasses prescription is first to understand all the complex abbreviations.


What do all the abbreviations on your eyeglass prescription mean? 

Let's start with what OD and OS stand for. OD means oculus dexter, Latin for the right eye, whereas OS means oculus sinister, Latin for the left eye. You may also see OU written, which refers to both eyes, or RE, right eye, and LE, left eye. 

How to read your prescription

Now that we've simplified what OD and OS stand for, let's dive into the various other abbreviations jotted all over your prescription. 

SPH: This means sphere. 

CYL: Stands for Cylinder and applies to astigmatism. 

AX: Meaning Axis. Similar to Cylinder, Axis is used to correct astigmatism. Therefore, Axis and Cylinder are always used together in a prescription. 

ADD: This means the added magnification is needed for progressive/bifocal lenses. 

PD: Stands for Pupillary Distance—the distance between your pupils. 

You have all of the abbreviations down, but how about understanding what they mean for the correction of your vision. 

How to read your eyeglass prescription:

SPH-Sphere: This is the primary correction for your eyes—measured in diopters. The numbers you see here refer to the lens power needed for each eye. Negative values indicate farsightedness, while conversely, positive values indicate farsightedness. 

You may see PL, DS, or 0 written here instead; these are used as space holders to specify that no corrections are needed for a specific eye.

How to read your prescription

Cyl and AX-Cylinder and Axis: These two values are used to correct astigmatism. Cylinder is the strength of the astigmatic correction, and Axis is the angle on which the correction must be applied. Cylinder and Axis, if present, are always prescribed together. Cylinder can be either positive or negative depending on your doctor's practices which should be uniform for both eyes. The numbers used in this section refer to angles in degrees ranging from 1 to 180 and not diopters. Here’s an example of what a prescription with astigmatism may look like:

How to read your prescription

PD-Pupillary Distance: This is the distance between your pupils and is used to help center a prescription correctly in your frames. Every prescription Frames purchase placed with Hubble requires a PD to fulfill the order accurately. Remember to request that your optometrist write your PD down on your prescription during your appointment. If you happen to have a script without a PD, there are ways to acquire your PD yourself by either measuring or utilizing an app. 

How to read your prescription

Other terms you may see on your prescription are Prism, a correction for muscular issues, and ADD, used for multifocal (progressive/bifocal) lenses. Hubble currently does not fill prescriptions for Prism or ADD, but that doesn't mean you can't understand what each means for your eyes.

How to read your prescription

Prism: Is used to correct vision displacement or double vision. The number you see written on your prescription refers to the number of diopters applied to compensate for vision alignment problems. 

ADD: This is only used for multifocal (progressive/bifocal) lenses and refers to the added magnifying power placed at the bottom of the lens. PAL is occasionally used by optometrists when the addition of progressive lenses is different compared to bifocals.  

Side Note: Hubble does not offer progressives (multifocal lenses); however, we do make glasses with either the prescribed reading or distance correction needed. 

You now understand how to read your prescription and are ready to purchase Frames by Hubble, but you’re not certain if we cover your vision needs. So, let’s clarify all the vision needs Hubble covers and get you on your way to finding new Frames you’ll love. 

What prescription lenses do Frames by Hubble offer? 

Hubble Frames offer single vision, readers, and non-prescription lenses and prescription or non-prescription sunglasses, all with the ability to upgrade to premium and/or treatments—Bluelight or thinner 1.67 High Index lenses. 

Hubble customers purchase prescription glasses to help correct 3 eye conditions, nearsightedness, farsightedness, and astigmatism. 

  • Nearsightedness (Myopia): You are able to see better near than you can at a far distance. 
  • Farsightedness (Hyperopia): You are able to see better far away than you can see close up. 
  • Astigmatism: A distortion in the eye that causes blurry vision. 

Eyeglass Prescription Types: 

Single Vision: These lenses correct one field of vision—near, intermediate, or distance. Single vision lenses have one correction in each lens and the prescription consists of Sphere, Cylinder, Axis, and Pupillary Distance. 

How to read your prescription

Readers: These lenses consist of only a Sphere, and offer simple magnification for things like reading. You do not need a prescription to purchase these lenses. 

How to read your prescription

Non-Prescription: These lenses offer no prescription correction and are commonly upgraded with blue light filtering lenses. 

Sunglasses: Hubble frames offer non-prescription, single vision, and reader sunglasses. Our sunglasses have a few limitations: 

  • We do not fill a sunglasses prescription if the Sphere is greater than -10.00 or +6.00.
  • We do not fill a sunglasses prescription if the Cylinder is greater than +/- 4.00.
  • We do not offer High Index for sunglasses at this time. 

What are Hubble’s eyeglass prescription ranges? 

The table below will aid you in determining if your prescription lands within the range of vision correction that Hubble currently offers. If you have any questions in regards to whether or not Hubble offers your vision correction feel free to reach out to our friendly customer service team via our Chat Portal 24/7, found on the bottom right-hand corner of our website, or email Hubble at One of our customer service reps would be happy to assist you!

What we don’t currently offer for eyeglass lenses: 

  • We do not fill a prescription if the Sphere is greater than -11.75 or +8.00.
  • For blue light lenses, we do not fill prescriptions greater than -9.00 or +7.00.
  • For astigmatism we recommend High Index if the Sphere is greater than +/- 2.50; we do not fill a prescription if the Cylinder is greater than +/- 4.00. 

Prescription Ranges

What else do Hubble Frames offer? 

All of our frames are custom built with anti-scratch, UV protection, and polarization. 

  • Anti-scratch: This feature guards lenses from any incidental contact from regular wear. 
  • UV-protection: This feature blocks UVA and UVB rays from harming your eyes.
  • Polarization: This feature enhances vision comfort by eliminating glare, increasing contrast, and improving color perception.

Our construction process includes actual humans—you’ll see our devotion to the craft right down to the minute details. Each pair of Hubble Frames is hand-assembled and polished to order before getting shipped out with a sleek carrying case and microfiber cloth for easy toting and maintenance. 

So, if Hubble offers your eyeglass correction needs give our various new frames collections a peek and shop away with Hubble Frames starting at just $48. And, as always, if you need more information or still have questions, don’t hesitate to reach out to us via chat or email us at We’re here to help you see the world clearly and affordably.