How to Find Out What Prescription Your Glasses Are (2023)

How to Find Out What Prescription Your Glasses Are (1)Share on Pinterest

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Over 150 million people in the United States wear corrective eyewear, designed to compensate for issues such as nearsightedness and farsightedness.

If you’re one of them, you know how expensive and time-consuming it can be to get a prescription and new glasses. Eyeglass prescriptions usually last from 1 to 2 years. If it’s been that long since you got your prescription, it may be better to see an eye doctor for a health checkup and to get your most up-to-date prescription and best fit.

If you have eyeglasses and you’re confident the prescription is up-to-date, you can try the GlassesUSA Prescription Scanner app to get your prescription details.

Keep in mind that the accuracy of apps like this to measure eyeglasses is unknown and, depending on your prescription, this is not the best way to measure the prescription of your eyeglasses.

In this article, we’ll go over the steps I took when trying to use the GlassesUSA Prescription Scanner app, as well as other options you have for figuring out the prescription of your glasses.

The GlassesUSA Prescription Scanner is a free app that uses your smartphone camera to scan your current eyeglasses and read the prescription. You’ll also submit a selfie photo to measure your pupillary distance (PD), the distance between your pupils.

How we tested the GlassesUSA Prescription Scanner app

I tried out the scanner app using:

  • my own eyeglasses, which are outside the app’s range: trifocal lenses with a complex prescription for presbyopia
  • a second pair of eyeglasses, with single vision lenses for nearsightedness in a simple prescription

How using Prescription Scanner went, according to our tester

(Video) How To Find Out Your Current Prescription? |

I’m a computer-literate, older woman with a complicated prescription. I wear trifocal eyeglasses, which include a prescription designed to address presbyopia, an age-related eye condition.

Scanning lenses that GlassesUSA doesn’t make

I knew that GlassesUSA wasn’t designed for my type of prescription, but out of curiosity, I completed the scan using my own eyewear.

How the first scan went

After doing all of the steps, a screen came up indicating that my glasses were out of range and couldn’t be read.

Even though this confirmed that I couldn’t use the app, it was good news because it showed that the GlassesUSA app read my prescription correctly, and gave me accurate information that it couldn’t be filled.

How the second scan went

I tried it a second time with my own eyewear so that I could get a better handle on all of the screens.

I was surprised that this second try brought a different result. The app took me through the entire process and continued to try to read my prescription at 99 percent complete for over 20 minutes. It never finished and never sent me an error message.

Scanning lenses that GlassesUSA can make

Next, I borrowed a pair of eyeglasses from my son, who’s nearsighted and has a simple prescription that fits within the GlassesUSA range. This range is for single vision prescriptions between -6.00 to +3.00 and cylinder up to -2.50.

Next, I go over the steps I took with his glasses, using the GlassesUSA app.

You can read more about the Prescription Scanner app on

1. Download the GlassesUSA app

  • From its website. Open up the GlassesUSA website on your computer. Towards the bottom of the homepage there’s a “download app” prompt where you can request the app link.
  • From the app store. You can also download the GlassesUSA app directly through the app store on your phone. It’s available for both iOS and Android.

2. Scan from the app

Once the app is opened, click “Start scan.” The app uses voice prompts to get you from one step to the next, which is very helpful.

3. Collect what you’ll need

The screen will show the tools you need to complete the scan. These are:

  • computer with a screen that measures 12” x 27”
  • standard magnetic card for scaling
  • your eyeglasses

What’s a ‘magnetic card’?

Cards with magnetic strips are generally the size of a standard credit card. These include gift cards, debit cards, and some ID and transit cards.

(Video) How to Read Your Glasses Prescription | Clearly

GlassesUSA describes using a “magnetic card” to take certain measurements and images for the scanning app.

We suggest using something without identifying markings and without account information on it.

4. Set up and calibrate your device

You’ll receive a web address to log into from your computer, where you’ll see a QR code to scan. This syncs your phone to your computer.

If your computer doesn’t have functional cookies enabled, you won’t be able to complete this step. While I did have cookies enabled I couldn’t complete this step in Google Chrome. I tried Chrome on another computer but got the same result. I had better luck with Microsoft Edge, and was able to scan the QR code through that.

Once the code is scanned, you’re prompted to scale the exact size of your computer screen, using a magnetic card. This sounds easy but may take several tries before it calibrates. If it doesn’t work instantaneously, you’ll have to hold the card flat against the screen. I had to adjust the screen up and down many, many times before it calibrated. This took multiple tries on two computers for around 15 minutes.

5. Scan your current pair of eyeglasses

Once things are calibrated, the app is ready to scan your glasses. You do this by holding your glasses midway between your phone and computer. You’ll be prompted to tilt your glasses repeatedly until they’re read. This takes around 3 minutes.

6. Take a photo for your PD measurement

You’ll be asked to take a selfie with the magnetic card held between your eyebrows. This is done to measure your pupillary distance (PD). This vital step ensures that the lens power of your eyewear is correctly centered.

GlassesUSA will then request your account information, and will provide you with your prescription, so that you can purchase glasses.

If you have a prescription on hand to compare your GlassesUSA prescription to, you can be better assured of its accuracy.

Privacy, please!

If information privacy is a concern to you, use any card that is credit-card sized (such as a library card) or cover information like numbers and names.


  • straightforward and easy to use
  • fast and convenient process in the comfort of your home
  • less expensive than visiting your eye doctor


  • errors can cause inaccurate prescriptions
  • your prescription may have changed
  • not suitable for strong and progressive prescriptions
(Video) Glasses and Contact Lens Prescription Explained | Eyes Explained

The GlassesUSA Prescription Scanner app is suitable for:

  • people in good health, age 18 years and older
  • people with stable vision satisfied with their current prescription
  • single vision prescriptions between -6.00 and +3.00
  • cylinder measurements lower than -2.50

It’s necessary to have a smartphone with a working camera, a desktop or laptop computer with at least a 12-inch (30-cm) screen, and a standard-size magnetic card. Plus, you’ll need your eyeglasses with your current prescription.

GlassesUSA has a 4.5 (excellent) rating on Trustpilot. GlassesUSA is accredited by the Better Business Bureau (BBB) and has a B rating. Customer reviews on the BBB website give GlassesUSA an average rating of 2.4, and there were 205 complaints filed in the last 12 months.

Positive reviews say the Prescription Scanner app is convenient to use, the process is smooth, and their prescriptions are accurate. Customers are satisfied with the wide selection of glasses and reasonable prices.

Many unfavorable reviews mention shipping delays, refund issues, and poor customer service communication. Some customers complain about hidden charges, the short 14-day return window, and receiving faulty products.

Just remember that you can request your prescription details from the office where you last had an eye exam. They’re required to share a copy with you.

If you’re looking for other options to find out your prescription based on existing glasses, there are other scanning apps like the one GlassesUSA offers.

  • Liingo RX Reader: Liingo Eyewear also has an app that you can use to get the prescription of your current glasses by downloading the app, calibrating hardware, and scanning your lenses.
  • GlassesOn app: 6over6 offers its GlassesOn app to take measurements similar to GlassesUSA Prescription Scanner to get PD and lens details.
  • Lens Scanner App: SmartBuyGlasses, an eyeglass retailer, partnered with 6over6 to offer its own version of an eyeglass scanning app.
What the Prescription Scanner app isn’t for

The app doesn’t accommodate:

  • strong or weak prescriptions
  • prism prescriptions used to correct double vision
  • multiple prescriptions within one lens, such as bifocals or multifocals
  • contact lens prescriptions

Frequently asked questions about the Glasses USA app

(Video) Optometrist explains: How to read your glasses prescription

Is the information reviewed by a qualified healthcare professional?

No, the information you provide to the Prescription Scanner app is not reviewed by a qualified healthcare professional. GlassesUSA does not offer medical advice.

Do eye doctors recommend finding out your glasses prescription online?

According to the American Academy of Ophthalmology, eyeglass prescription apps and home vision tests are suitable for people 18 to 39 years old with healthy eyes and a mild or moderate prescription.

But they are not advisable for people who have a strong or complicated prescription, an eye condition, or a condition that increases their risk for eye disease, including diabetes or a family history of glaucoma.

Anyone who hasn’t had an eye examination for 1 to 2 years should visit an eye doctor to update their prescription.

Do I need an internet connection to find out what prescription my glasses are?

If you want to use an app to determine your prescription, you’ll need a strong internet connection and a device to scan your current eyeglasses.

How accurate are the measurements from the GlassesUSA app?

The prescription measurements from the GlassesUSA app are fairly accurate though the exact accuracy is unknown. But the app has a higher margin of error and is less accurate than tests that an optometrist or ophthalmologist performs.

How do you know when your prescription is no longer for you?

There are several symptoms that may suggest it’s time to visit an eye doctor for an updated prescription, including:

  • headaches
  • blurry vision
  • eye fatigue

If it’s been more than a year since your last eye exam, it’s time to make an appointment, too.

How often should I change my prescription?

Your eye prescription will likely change throughout your life. If you have any issues with your eye health or vision, try to visit your eye doctor every year for an updated prescription.

Your eye doctor will perform a comprehensive exam and let you know whether your prescription has changed.

Can I have multiple prescriptions at once?

It’s possible to have multiple eye prescriptions at once. This may happen if your eye doctor prescribes bifocal or multifocal lenses.

These lenses contain more than one prescription within the same lens to help you see clearly at different distances.

There are several online retailers, including GlassesUSA, where you can have your current eyewear prescription read.

Some retailers also offer vision checks, which are assessed by ophthalmologists. But according to the American Academy of Ophthalmology (AAO), these aren’t as accurate as in-person exams and these vision checks don’t assess eye health.

These services may be less expensive for purchasing eyewear than some brick-and-mortar retailers.


They are typically best for simple prescriptions. If you wear bifocals or have any other type of complex or strong prescription, seeing an eye doctor in person may be your best first step.

Once your prescription is in hand, you can use an online retailer, if you choose.


Do the numbers on my glasses tell me my prescription? ›

These numbers represent diopters, the unit used to measure the correction, or focusing power, of the lens your eye requires. Diopter is often abbreviated "D." For example, if your prescription says -1.00, you have one diopter of nearsightedness. This is a fairly mild amount of nearsightedness.

Can I find out my eye prescription online? ›

People can use apps, such as GlassesUSA's app, to find out their eyeglass prescription. Alternatively, for a small fee, some websites offer an online eye exam. This may be more suitable for people who do not have a current prescription.

What do the numbers on my glasses mean? ›

The numbers beneath the frames reflect the SIZE MEASUREMENTS in millimeters (mm). THE FIRST NUMBER (ex.54) = the width of the lenses. THE SECOND NUMBER (ex.15) = the distance between the lenses. THE THIRD NUMBER (ex.140) = the length of the temple arm including the portion going behind the ear.

Are my glasses supposed to have numbers on the lenses? ›

The First Number

Each has a specific meaning, but all are meant to reflect the size measurements of the glasses. The numbers on the glasses you wear will have different markings than glasses worn by someone who has a head of a different size. The first number listed gives the width of the lenses.

How do I check the power of my glasses at home? ›

Option #1: Use a Printable Diopter Reading Test Card

With the printed sheet 14″ away, attempt to read the top line without reading glasses. Continue down the chart until you find a line you can read clearly without your glasses on – this is the diopter (power/magnification) you need.

What do the 3 numbers on glasses frames mean? ›

You'll find up to three numbers on glasses frames, and they stand for the lens width, bridge width, and temple length. These numbers are written on the inside of one arm and may be separated by spaces or dashes. Often, a small square shape separates the lens width from the bridge width.

Why do my glasses lenses have letters on them? ›

The markings are there for the optician or laboratory to be able to identify the major fitting reference points on the lenses so that they can be placed in the frame properly. The markings can also be used to identify fitting issues if a wearer has a visual problem after the glasses are dispensed.

What are the letters on my glasses? ›

The letters indicate material and lens design. Numbers can indicate add power or lens material depending on the manufacturer.

Is minus 7 legally blind? ›

In the United States, a person has legal blindness if: Their vision with glasses or contacts is 20/200 or worse. Their visual field is 20 degrees or less in the better-seeing eye.

What is the normal power of eye glasses? ›

The optical power of a healthy human eye is about 40 diopters, meaning the ability to focus on an object or image 1/40 of a meter from the eye. The eye of a typical young person can adjust an additional 20 diopters. By age 25 this focusing flexibility is usually reduced to about 10 diopters.

What is the highest eye power? ›

20/10 vision is thought to be the maximum visual acuity of human eyes without binoculars or other magnifying devices.

How do you figure out your eye number? ›

To get the right number, you need to do a little math. To find the right reading glasses, add the sphere number to the ADD number. In the above example, for the right eye, this would be -2.00 and +1.75, which equals -0.25. For the left eye, add +1.00 and +1.75 to get +2.75.

What is astigmatism in your eye? ›

Astigmatism is a common eye problem that can make your vision blurry or distorted. It happens when your cornea (the clear front layer of your eye) or lens (an inner part of your eye that helps the eye focus) has a different shape than normal. The only way to find out if you have astigmatism is to get an eye exam.

What is the strongest number for reading glasses? ›

What are the highest and lowest-strength reading glasses available? The lowest-strength reading glasses have powers of +0.25 diopters, whereas high-strength ones can go well beyond +2.50 diopters—in rare cases, all the way up to +4.00.

Can I get a copy of my eye test prescription? ›

The optician is legally obliged to provide you with a copy of your prescription after your eye test. If they don't give you this, make sure you ask them.

Can I ask my optician for my prescription? ›

Following an eye test your ophthalmic practitioner is legally required to give you your optical prescription or a statement to say you've been referred for further tests.

Can I get a copy of my prescription from optician? ›

An optician is obliged to provide you with the written prescription following the eye examination. You are then able to take the prescription to another practice. By law, the prescription must provide the basic results of the eye examination.

Can I get another copy of my eye prescription? ›

Regardless of reason, you are free to choose. And, you can take your prescription from one optician to another optician. You can take your prescription to another optician and buy glasses from another practice. You should get the written prescription, following the eye examination, from your optician.

How do I get a copy of a prescription? ›

By speaking to your GP surgery

Ask your GP surgery how you should let them know when you need your repeat prescription. They can send your request to a pharmacy. You might be able to get your medicine sent to you if the pharmacy you have nominated offers that service.

What is a strong eye prescription? ›

-3.00 diopters or less is mild. -3.00 to -6.00 diopters is moderate. -6.00 to -9.00 diopters is severe. -9.00 diopters or more is extreme.

How long do eye prescriptions last? ›

So how long is an eyeglass prescription good for? Typically one to two years, but we recommend checking your prescription expiration date. That being said, if you are at higher risk of vision changes, your glasses prescription expiration date might be one year, rather than two, after your last exam.

What do you do if you lose your glasses prescription? ›

Here's what you should do if you lose or break your glasses while traveling.
  1. Go to a local eyeglass shop. ...
  2. Seek out an optometrist. ...
  3. Use a ride-sharing service. ...
  4. Buy temporary reading glasses.
  5. Pull out the spare pair. ...
  6. Store your glasses in a hard case. ...
  7. Pack a repair kit. ...
  8. Know your prescription.

Can I get new glasses with an old prescription? ›

Unfortunately, you won't be able to get a prescription filled without a new exam if your prescription has expired. It is actually illegal for someone to fill an expired glasses prescription. Even if you think your vision hasn't changed, you still need to get a new exam before you get new glasses.

How can I get my glasses prescription without going to the doctor? ›

In-Store Optician Prescription

The other most traditional venue for securing a prescription is going to an eyeglass store to have your eyes checked by the in-store optician. After a short 10-minute evaluation of your vision, your results will be reviewed by a doctor, and they'll provide you with a prescription.


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2. Vision Test Tips - Remove Anxiety and Get Perfect Prescription Glasses - Eye Doctor Explains
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3. How to read a glasses prescription for beginners to your advantage
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4. Your Eyeglasses Prescription Explained: How To Interpret Your Glasses and Contact Lens RX
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