A Breakdown of Common Terms Like OD, OS, Sphere, and Cylinder
If you’ve ever looked at your eye prescription and felt like you were reading another language, you’re not alone! Those abbreviations and numbers can seem confusing at first, but they hold the key to understanding your vision needs. At Eyecare First, we believe in educating our patients, so they feel confident about their vision. Let’s break down the most common terms you’ll see on your prescription.
OD vs. OS: Right vs. Left Eye
- OD (Oculus Dexter): Refers to your right eye.
- OS (Oculus Sinister): Refers to your left eye.
- Sometimes, you’ll also see OU (Oculus Uterque), which means “both eyes.”
Sphere (SPH): Your Lens Power
This number tells you the strength of your prescription. It corrects nearsightedness or farsightedness.
- A negative (-) number means you’re nearsighted (you see better up close).
- A positive (+) number means you’re farsighted (you see better at a distance).
Cylinder (CYL) and Axis: Astigmatism Explained
If you have astigmatism, the shape of your eye is slightly irregularly shaped, causing blurred vision.
- Cylinder (CYL): Measures the severity of astigmatism. If there’s no number here, you don’t have astigmatism.
- Axis: A number between 1 and 180 degrees that tells us the orientation of your astigmatism correction.
ADD: Reading Power for Bifocals & Progressives
- This number appears if you need bifocals, progressives, or reading glasses. It’s an additional magnifying power that helps with near vision (common in patients over 40).
Prism: Correcting Eye Alignment
- Some prescriptions include prism to help with eye alignment issues, such as double vision or strabismus (eye misalignment).
Your Prescription, Your Vision
Understanding your prescription helps you make informed choices when selecting glasses or contacts. At Eyecare First, we use advanced technology to ensure your eyewear is customized for your best vision and comfort.
Have more questions? Schedule an eye exam today! Let’s make sure your vision is clear and stylish with our quality frames.
📍 Book your appointment at Eyecare First in Norwood, NJ!