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How to Read Your Eye Prescription

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How to Read Your Eye Prescription

How to Read Your Eye Prescription

Picking up your fave glasses and sunnies in your exact prescription is easy with QUAYRx. As long as you have an unexpired prescription, you’re good to go. But naturally, you might wonder what all those numbers from your optometrist mean. If you’re unclear about your Rx, you’re not alone. Wondering how to read an eye prescription? We’ve got you covered with the ins + outs below. 

Glasses Prescription Overview

With so many numbers and abbreviations on your prescription, things can get confusing. Let’s start out with eye prescription basics. Here’s a quick and easy mini glossary of what those abbreviations and numbers on your Rx mean.

Eye Prescription Abbreviations

Providers use all kinds of shorthands to write eye prescriptions, including Latin terms. Before you get to your measurements, you'll see rows starting with abbreviations such as “OD” and “OS” to indicate which eyes have which numbers. Here's the deal on all of that below — it's all relatively straightforward. 

  • OD: Oculus dexter in Latin means “right eye.”

  • OS: Oculus sinister in Latin means “left eye.” 

  • OU: Oculus uterque in Latin means “both eyes.”

Eye Prescription Scale

Now, let's talk about measurements. The eye prescription scale goes by diopters, AKA the unit that measures the correcting power of the lens that your eye needs. You’ll usually find diopters abbreviated as “D.” A plus (+) sign in front of a number indicates farsightedness, while a minus (-) indicates nearsightedness. Here's a quick refresh on those terms: Farsightedness refers to when you have trouble seeing things up close, whereas nearsightedness is when you struggle with seeing things far away. The further away the prescription number is from 0, the stronger your prescription will be. At the end of the day, there's no such thing as a "bad" prescription, but we'll talk more about that below. 

What Do the Other Terms on Your Eye Prescription Mean?

Now that we know the indicators and measurement systems on an eye prescription, we can get into the nitty-gritty of those numbers. For example, what is “SPH” for glasses anyway? Sphere, cylinder, axis, and pupillary distance are the basics, but you might notice other numbers and symbols as well. 

  • SPH/S: The sphere, taken in diopters, is the power of the lens that will correct your eyesight. This number indicates nearsightedness or farsightedness. If you see an infinity sign or plano (PL) where the sphere number should be, you don't need prescription lenses.

  • CYL/C: The cylinder, taken in diopters, indicates the amount of astigmatism in your eye. The number means the power of the lens needed to correct astigmatism, AKA when your eye's cornea or lens has an imperfect curve. 

  • Axis: The axis number, which will be between 1 and 180, lets you know where on your eye your astigmatism is. As opposed to diopters, this number is measured in degrees. 

  • PD: Pupillary distance is the distance from pupil to pupil. It lets opticians know where to center your prescription. 

  • ADD: The “ADD” number, taken in diopters, is the number “added” to the distance prescription to help with reading. It’s usually for those with presbyopia, an age-related condition that makes it difficult to see things nearby as you grow older. Those who don't opt for separate readers may get progressives or bifocals with an additional ADD number. 

  • Prism: Another term you might see is “prism.” A prism measurement is usually only indicated if you have crossed eyes (strabismus) or other conditions that cause double vision. Taken in diopters, it shows the prismatic power needed to correct the differences in eye alignment. In addition to the prism value, you’ll see an indicator for base, AKA where the prism will be placed on your eyeglasses; you may get indicators for base up (BU), base down (BD), base in (BI), or base out (BO). 

Eye Prescription Chart Example

Your eye prescription will usually read as Sphere x Cylinder x Axis if you have some form of astigmatism. For distance vision, you’ll have two rows with measurements, one for “OD” (your right eye) and another for OS (your left eye). Your optometrist may also have an additional column or row for an ND (near distance) or ADD number — this is to make multifocal lenses (either bifocals or progressives) for near-vision or reading. Additionally, your glasses may have columns for prism and base measurements for correcting eye alignment issues. 

Here’s an example of what your eyeglass prescription might look like:

Rx

SPH

CYL

AXIS

ADD

OD

-1.00

-1.00

90

OS

-1.25

-0.75

100

Are Eyeglass Prescriptions Different From Contact Prescriptions?

Here’s a quick FYI on contacts: Contact lenses will have different numbers than your eyeglasses because they sit right on top of your eyes. In most cases, the measurements will be specific to the size and brand of your contacts. You will need to get a separate eye exam and do a contact lens fitting if you opt for contact lenses. But even if contacts are your preferred choice of vision correction, it's a good idea to get back up glasses just in case you can’t wear your contacts for any reason — plus, having specs gives you the opportunity to flex in different head-turning styles. 

square clear lenses and frames

There Is No Such Thing as a Bad Eye Prescription

When people talk about “bad” eye prescriptions, they usually mean that myopia (nearsightedness) or hyperopia (farsightedness) in their eyes have high numbers. But vision is a complex result of environment and genetics; no eyesight measurement is inherently "bad." It's best to consider your vision correction options with your eye care provider to address any issues you may have. 

What Are Considered “High” Prescriptions? 

Doctors refer to high myopia as a diagnosis of -6 diopters or higher. It usually first appears in childhood but can also be found in adulthood due to visual stress or diabetes. On the other hand, high hyperopia is +5 diopters or higher. It’s also usually a condition that first appears in childhood, and those with it are at an increased risk of developing lazy eyes or eyes that do not look in the same direction.

Your prescription can change over time; small fluctuations are typically common, but you should always talk to your optometrist about any vision concerns. At the end of the day, it’s QUAY to take care of your health and get regular eye exams. 

Getting Your Prescription Filled From QUAY

What Is Included With a QUAY Prescription Frame?

At QUAY, we fill prescriptions with single vision between +4 to -6 and astigmatism of +/-4. We make prescription glasses and sunglasses, so you can have a pair handy for werk on Zoom and playing outside. Prices are all-inclusive with the werks you need, so you don’t need to pay extra for add-ons. Here are the deets: Starting at $95, QUAY prescription glasses include high-index lenses, UV protection, blue light technology, anti-reflection, smudge resistance, and scratch- resistance — in addition to your frames and prescription. Starting from $150, QUAY prescription sunnies include high-index lenses, UV protection, anti-reflection, and scratch resistance.

What If I Have a Progressive Prescription?

If you have a progressive prescription, we’re happy to make single-vision lenses from your Rx. After you submit your order, one of our QUAYRx Customer Care Associates will reach out to you. 

Which Styles Can I Get With QUAYRx? 

If you’re looking for just the right style, choose from over 200 Rx picks at QUAY — including fan fave OGs such as HIGH KEY MINI and NOOSA. All you need is an unexpired prescription from your optometrist to submit at checkout, and you're all set. 

Seeing clearly never has to be drab. To keep your vision and style on point, shop the QUAYRx Collection for notoriously cool prescription glasses and sunglasses.

This blog post has been peer reviewed by Ryan Boydon, licensed Optician.

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