How To Read Your Glasses Prescription - Fitz Frames

When you look at your prescription, you will see most or all of the following descriptors: Spherical (SPH), Cylindrical (CYL), Axis (AX), Add, and Prism. Sounds pretty technical… and incredibly confusing. So, let’s break it down.

Spherical (SPH) is the indicator for nearsightedness (myopia) or farsightedness (hyperopia). If you see a minus sign (-) next to your number in this box, it indicates that you need a negatively adjusted lens to compensate for nearsightedness. On the other hand, if you see a positive sign (+) next to your number in the box, it’s indicative that they’ll need a positively adjusted lens to compensate for farsightedness. In easier words, Nearsightedness (-) means you see objects that are closer clearly, but your vision gets worse the farther away you get. On the flip side, farsightedness (+) indicates that you see objects far away clearly, but they get blurrier as they get closer. Regardless of your prescription, the word “sphere” shows that it is a prescription that is equal in all parts of the eye.

Cylindrical (CYL) and Axis (AX) are both measurements used in reference to an astigmatism. According to the American Optometric Association, an astigmatism is when “an irregularly shaped cornea or lens prevents light from focusing properly on the retina… As a result, vision becomes blurred.” CYL refers to how flat or irregularly-shaped your cornea is and AX is the degree (from 0-180) that details exactly where your astigmatism is located on your cornea. If one or both of your eyes have no astigmatism, your doctor may just leave these blank or mark DS (short for diopters) to indicate that they checked and that eye (or eyes) didn’t present an astigmatism.

Add is any additional magnifying power that needs to be added to the lower part of your lenses . This is commonly used in bifocals, trifocals, and progressive lenses to address Presbyopia, a natural loss of the eyes’ ability to focus on nearby images that is caused by aging.

Prism and Base are used when an eye has a vision problem that causes someone to see double or blurred vision and is NOT due to a refractive error. In layman’s terms, when an eye has a prism/base prescription, it is because a person’s vision deviates and consistently positions images where they are not supposed to go. This is shown in people whose eyes tend to cross or in those that seem as though they have a wandering eye.

So, there you have it! The ins and outs of decoding your prescription. We hope this is helpful and feel free to message us on Facebook or Instagram if there are any other eye-related topics you’re dying to know more about!

-The Fitz Team