How to Read an Eye Prescription (Simple Guide)- Prime Magazine

How to Read an Eye Prescription — Easy Guide to Understand Your Vision Results

Reading an eye prescription may look complicated at first, but it’s easier than you think. Once you understand what each value means, you’ll know exactly how your eyes are being corrected.

🔍 Sphere (SPH)

The sphere value shows whether you are nearsighted or farsighted.

A negative (-) value means you are nearsighted (myopia) and need help seeing distant objects clearly.
A positive (+) value means you are farsighted (hyperopia) and need help focusing on nearby objects.

The farther the number is from zero, the stronger your lens power will be.

👁️ OD and OS

You’ll also notice the abbreviations OD and OS:

OD (oculus dexter) refers to your right eye.
OS (oculus sinister) refers to your left eye.

Sometimes, you may see OU, which means “both eyes.”

⚖️ Cylinder (CYL) and Axis

If you have astigmatism, you’ll see a cylinder (CYL) value on your prescription. This number shows how much correction your lenses need to smooth out uneven curvature in your eye.

The axis value (from 0° to 180°) tells the optician the orientation of that correction. It does not measure strength—it simply indicates direction.

➕ Addition (ADD)

If you use bifocals or progressive lenses, your prescription includes an ADD value. This number indicates the extra magnifying power you need for reading or other close-up tasks. For example, an ADD of +2.00 means your near vision requires two diopters of additional correction.

🔺 Prism (PRISM)

In some prescriptions, you’ll find a prism value. This adjustment helps correct eye alignment or binocular vision problems such as double vision.

Prisms are measured in diopters (Δ) and are labeled by direction:

Base In (BI) or Base Out (BO) correct horizontal alignment.
Base Up (BU) or Base Down (BD) correct vertical misalignment.

These lenses redirect light to help your eyes work together comfortably.

📏 Pupillary Distance (PD)

Your pupillary distance measures the space between the centers of your pupils. This ensures that lenses are properly aligned with your eyes, providing clear, strain-free vision.

🧾 Example Prescription

Let’s look at this sample:

OD: -1.50 -0.75 × 180
OS: -1.25 -0.50 × 170
ADD: +2.00

Here’s what it means:

Both eyes are nearsighted because the sphere values are negative.
The cylinder values (-0.75 and -0.50) show astigmatism, which can blur both near and far vision.
The axis values (180 and 170) tell the lab where to position the correction.
The ADD value (+2.00) adds strength for reading or close work.

With this information, your optician can make lenses that match your unique vision needs.

✅ In Summary
Once you understand the meaning of each value—Sphere, Cylinder, Axis, and ADD—reading your eye prescription becomes straightforward. These numbers help your eye care provider create lenses that give you the clearest and most comfortable vision possible. PRIME

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PRIME Magazine

PRIME is a bi-monthly health and lifestyle magazine for those aged 40 and above. Published since 2006 by Spring Publishing, it features inspiring cover stories of celebrities, as well as other health and lifestyle information. Prime has also featured leading celebrities such as Brad Pitt, Matt Damon, Tom Hanks, Julia Roberts, Angelina Jolie, Kate Winslet, Mary Buffett, and many others.

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