How Bad Is My Eye Prescription?

How Bad Is My Eye Prescription? What The Numbers Mean

Written by True Eye Experts

Reading your eye prescription can be tricky – there are many symbols and numbers to decipher. However, we shouldn’t ask ourselves “how bad is my eye prescription?” but rather how can we best correct our vision to improve our eyesight? 

It’s easy to feel overwhelmed when reading all those numbers and symbols, but they are just a way to convey common eye problems. We have the answers to all your questions about eye prescriptions here. 

How To Read Your Prescription

There are rows labeled “O.D.” and “O.S.” on any vision prescription. The first, O.D. or oculus dexterous, is for your right eye, and the latter, O.S. or oculus sinister, is for your left. “O.U.,” also known as oculus ulterque, refers to both eyes. However, the symbols and abbreviations go beyond identifying each eye.

Here’s a quick guide on how to read your prescription:

  • + sign — A plus sign may appear like +1.00 or +2.00 on your vision prescription, which means that your lenses will help correct farsightedness. These lenses help see objects nearby, eliminating blurriness.
  • – sign — A minus sign will look like -1.00 or -2.00 on your vision prescription, indicating your lenses will be used to correct short-sightedness. Your glasses will help you see objects far away that currently seem blurry.
  • Numbers — Numbers convey a measure of your vision prescription. The larger the number, whether it shows a plus or minus symbol, indicates that you need a stronger prescription. 
  • SPH — This abbreviation stands for Spherical Correction and means that the level of nearsightedness or farsightedness is uniform across the eye. You’ll find this as one of the first numbers listed on your prescription.
  • CYL — CYL refers to cylindrical correction and indicates that you have an astigmatism. It means that the eye has mismatched curves and can cause blurred distance and near vision.
  • ADD — ADD refers to the strength of the lens to magnify objects. It’s mainly for those who need a separate prescription to see things up close and might look like ADD: +1.75 OU on your prescription.
  • AXIS — AXIS tells the lens maker where to put the astigmatism correction (or CYL) in the eyeglass lens.
  • P.D. — PD stands for pupillary distance and refers to the space between the centers of your pupils. The lens maker will customize glasses to your specific measurements so they are comfortable to wear and optically accurate.
  • PRISM — A prism is added to the lens to correct any issues hindering the eyes from working together. Prism is usually added to a prescription to help with double vision resulting in the misalignment of your eyes.

Is My Prescription Bad?

Remember, your prescription isn’t “bad.” Your eyes simply need help to see better. Your prescription is a measurement that indicates what is required to keep your vision at its very best. The aim of wearing glasses or contact lenses is to correct your vision. 

How Eyesight Changes

Everyone’s eyesight changes over time due to aging. For example, a child’s vision doesn’t fully develop until seven years old. An adult’s eyesight also evolves, but those changes are often more gradual than that of children.

With age, the eye and its muscles become weaker and stiffer, making it harder for the eyes to adjust to light and darkness and can make it difficult to see when driving at night. 

Some common eye conditions include:

  • Glaucoma is a group of eye conditions that damage the optic nerve and can permanently damage vision. Oftentimes, the condition is correlated with high eye pressure which can cause damage. It is the leading cause of blindness in adults over 60.
  • Cataracts occur when the lens of your eye, which is usually clear, begins to cloud, resulting in blurry vision.
  • Age-related macular degeneration occurs when a part of your retina called the macula is damaged, impacting your central vision and causing blurry vision.

When To Schedule An Appointment

To maintain optimal eye health, you should schedule an eye exam once per year. An annual eye exam does more than determine your prescription. By visiting your optometrist regularly, you are more likely to detect eye conditions or diseases early.

If you are experiencing any of the following symptoms, you should schedule an appointment with one of our True Eye Experts today:

  • Headache
  • Red, dry, or itchy eyes
  • Floaters or flashes of light
  • A family history of diabetes or glaucoma
  • Eye strain or motion sickness
  • Difficulty reading objects up-close
  • Any changes in eyesight, especially after experiencing injury or trauma
  • Difficulty driving at night

Of course, if you can’t remember the date of your last appointment, it’s time to schedule an eye exam. An annual exam is the best way to ensure you update your prescription regularly.


If you need help reading your vision prescription, reach out to your eye doctor to help better understand it. While eyesight changes over time, it’s not a matter of “how bad is my eye prescription,” but rather “what’s the best corrective solution for my vision?” To ensure you’re achieving your optimal vision and eye health, book your annual eye appointment today.

About the Author

True Eye Experts

Our mission at True Eye Experts is simple — provide the best possible care to our patients. We make sure we’re doing this a few different ways. Our V-Eye-P Exam is one of the most comprehensive eye exams in the industry. We use state-of-the-art medical technology to screen, diagnose, and treat more conditions than most other providers in the area. We have an extensive collection of designer eyewear that can complement any patient’s face, style, and budget, and our advanced contact lens fitting process can help even “hard-to-fit” patients wear contacts comfortably. Book an appointment online at one of our True Eye Experts locations, conveniently located throughout Central Florida. Have questions or prefer to book over the phone? Give us a call today.


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