When you read your glasses prescription, do you feel like you're staring at Egyptian hieroglyphics? From CYL to SPH, the mix of numbers and abbreviations can get confusing. That's why we made this blog - so keep reading!
Key Takeaways
- Your eyeglass prescription may have a CYL value, axis value, and SPH value.
- SPH values indicate the amount of lens power needed to correct myopia or hyperopia.
- However, SPH doesn't necessarily represent the amount of presbyopia or astigmatism present.
- A negative (-) SPH value indicates nearsightedness, while a positive (+) SPH number would point toward farsightedness. The farther the number is from 0, the more correction needed.
See Related: What Are Blue-Light Glasses, and What Do They Do?
How Do You Read Your Eyeglass Prescription?
When you read your glasses prescription, you might see a maze of numbers and letters. Fortunately, it's not necessary for you to decode their meaning - this prescription is just meant for your optometrist and optician.
But, of course, it can be helpful or interesting to understand it yourself!
Here are a few things you may notice on your eyeglass prescription:
- O.D. - This is short for oculus dexter, and refers to your right eye.
- O.S. - This is short for oculus sinister, and refers to your left eye.
- Axis - The axis value indicates the orientation of an astigmatism.
- CYL - CYL, or cylinder, indicates the lens power.
- SPH - SPH, or sphere, indicates a spherical correction of an astigmatism.
Bonus: What Does Axis Mean On My Prescription?
What Does SPH Actually Mean?
SPH, or sphere, is one value that you may see on eyeglass prescriptions. It's short for spherical power, and can either be negative or positive.
In short, SPH refers to the amount of lens power needed to correct myopia (nearsightedness) or hyperopia (farsightedness).
A minus sign or negative number means that you are nearsighted - far-away objects are blurry, but close-up objects are clear. A positive number or plus sign, on the other hand, means the opposite - close-up objects are blurry, and far-away ones are clear.
But for some, your SPH may be 0. That means that you are neither farsighted nor nearsighted. However, a SPH of 0 doesn't guarantee crystal-clear vision. That's because SPH doesn't account for presbyopia or astigmatism correction.
The Role of SPH in Vision Correction
So, we've established what SPH is. But why is it needed? What does it do? Why is it important?
To understand how eyeglass prescription values are used, it's important to know how corrective eyeglasses work.
Corrective eyewear bends the light that enters your retina. That's where SPH comes into the picture. It tells your eye care professional how much correction is needed! The farther from 0, the more correction is needed.
For example, a SPH of -1.00 indicates a mild myopia, while a value of +4.00 would indicate a severe hyperopia. The -1.00 prescription would require less correction than the +4.00 prescription.
Wrapping Up
Understanding your glasses or contact lens prescription is helpful if you use corrective eyewear. Whether you have astigmatism or nearsightedness, it can be beneficial to have a solid grasp of your own prescription!
Schedule an appointment at our Seattle-based clinic and boutique if you're ready to update your prescription, select new frames, and achieve clear vision. We're here to help you see and be seen in a new way!
Keep Reading: Are Cat-Eye Glasses in Style for 2025?
People Also Ask
What Is a Normal SPH Value for the Eye?
A normal SPH value for the eye can range between 0.00 and +/- 20.00.
What Does a +0.75 Sphere Mean?
A SPH value of +0.75 would mean a mild level of farsightedness. A positive value indicates farsightedness, while a negative number indicates nearsightedness.
What Does SPH +0.25 Mean for Glasses?
A SPH value of +0.25 would likely indicate a mild level of farsightedness in an individual.
What Is the Difference Between SPH and CYL?
SPH and CYL both represent different values for vision correction. A SPH value indicates a correction for distance or near vision, while CYL indicates an astigmatism correction.
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Oculus Eyecare is Seattle’s premier optometry practice and optical boutique for those looking to see and be seen in a new way. Located in South Lake Union on Denny Way, Oculus Eyecare offers comprehensive eye care services and exams for individuals and families in Seattle. Click here to schedule an appointment or a personal styling session. To stay connected and learn more, follow us on Facebook, Instagram, and X/Twitter.