You've just had your eye exam, and you're ready to order new glasses. You open the prescription, and... it looks like a secret code. SPH? CYL? ADD?
It’s confusing, and it's the #1 thing that makes ordering online feel overwhelming.
As your SF-based eyewear experts with over 20+ years of experience, we're here to translate it for you. It's much simpler than it looks.
First, the Basics: Which Eye is Which?
Your doctor uses Latin, but it's simple:
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OD (Oculus Dexter) = Right Eye
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OS (Oculus Sinister) = Left Eye
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OU (Oculus Uterque) = Both Eyes
Understanding Your Key Numbers
Here are the main terms and what they mean in plain English.
SPH (Sphere) This is the main power of your lens, correcting for nearsightedness or farsightedness.
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A minus sign (-) means you are nearsighted (things far away are blurry).
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A plus sign (+) means you are farsighted (things up close are blurry).
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If you see "Plano," "PL," or "0.00," it means you have no correction for that eye.
CYL (Cylinder) & AXIS These two numbers always work together.
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CYL is the power that corrects for astigmatism, which is a common and minor curve on your eye (shaped more like a football than a baseball).
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AXIS is a number from 1 to 180. It just tells us the direction of that astigmatism. You will only have an AXIS if you have a CYL.
ADD (Addition) This is the "added" magnifying power for reading. You will only see this number on your prescription if you wear bifocals or progressives to help you see things up close.
How to Enter Your Numbers (It's Easy!)
Sometimes, doctors write "1.00" and sometimes they just write "100." They mean the same thing. Here’s how to translate:
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-25or-0.25→ Select -0.25 -
-100or-1.00→ Select -1.00 -
+200or+2.00→ Select +2.00 -
If your CYL column says "SPH" or "DS," that's just a fancy way of saying "0.00." → Select 0.00
A Note on Stronger Prescriptions (High-Index Lenses)
Our promise is to provide the best value and the best vision. Every frame we sell includes free, high-quality clear single-vision lenses.
However, to ensure the best, thinnest, and most comfortable glasses, prescriptions with a SPH over ±4.00 or a CYL over ±2.00 often require a special, thinner high-index lens.
This is a premium lens material that makes a huge difference in how your glasses look and feel. This is offered as a simple, affordable upgrade at checkout.
What About PD and PRISM?
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PD (Pupillary Distance): This is the crucial distance between your pupils. It's usually a separate measurement. We have a whole guide for it! [Link] Click here for our 2-Minute Guide to Measuring Your PD at Home.
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PRISM: This is a less common correction for specific eye alignment issues. If you see "Prism" or "Base" (BI, BO, BU, BD) on your prescription, please contact our expert team so we can ensure your order is 100% accurate.
Still Confused? Let Our Experts Handle It.
This is our job, not yours. As a passionate, SF-based small business with 20+ years of experience, our greatest value is our expert support.
Simply snap a photo of your prescription and email it to us at info@choiceeyewear.com
We'll read it for you, answer any questions, and make sure your order is perfect.
