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

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.

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

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.

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) How to Read Your Glasses Prescription | Clearly

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:

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

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

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.

(Video) Five Signs That Tell You To Change Your Prescription Glasses!

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.


Can I check my glasses 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.

Is your PD written on your glasses? ›

Where is my PD on my prescription? Your PD number will be in the 'PD' or 'pupillary distance' section of your eyeglass prescription. This is often separate from the 'grid' section of your prescription - where the doctor writes out the main prescription information.

What do the numbers on the side of my glasses 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.

Is there an app that can read your glasses prescription? ›

The Prescription Lens Scanner is a free app that scans your current lenses to reveal your glasses prescription. *The Prescription Lens Scanner eyecare prescription free app reads the prescription in your lenses. It does not replace an eye exam, and your current prescription must be valid.

How long are glasses prescriptions good for? ›

Eyeglass lens prescriptions typically are valid for a minimum of one year, or the minimum required by state law. It's very common for the expiration date on an eyeglass prescription to be the date two years from the day of your eye exam when the prescription was written and given to you.

Is your prescription on your glasses the same as contacts? ›

The answer is no. While they both have the same objective — to correct what eye doctors call “refractive errors” that prevent you from seeing correctly — prescriptions for eyeglasses and contact lenses are distinctly different.

Why isn't my PD on my prescription? ›

Your eye doctor might use PD to check parts of your vision or eye function, but it's not usually important for managing your vision treatment. That's why it's not on your prescription even though you need it when you're ordering glasses.

What happens if you wear glasses with the wrong PD? ›

This measurement is used to determine where you look through the lens of your glasses. If the PD is wrong, or as we say in the optical world “out of tolerance,” you won't be able to focus your eyes together properly. That's why it is important to make sure that your PD is as accurate as possible.

Can I measure my PD with my phone? ›

EyeMeasure enables you to measure your Pupillary Distance (eye to eye) & now Segment Height instantly at near and far distances. No mirrors, credit cards, tape measures or objects needed. It's accurate to up to 0.5mm for the perfect prescription glasses. Please note: iPhone X or newer is required for this app.

Is 0.25 eye prescription bad? ›

Myopia 0.25 is the smallest degree of myopia, usually does not affect too much to daily life, study and work. If you have myopia of only 0.25 degrees, you can do normal activities without wearing glasses at all.

How do I check my power specs? ›

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.

Why are there numbers on the bottom of glasses? ›

These numbers are the measurements that indicate and describe the size of your eyeglass frames, specifically: 1) The eye size number (it is the size of the lenses on your frame). 2) The bridge size number (the distance between the lenses).

Can Walmart read my glasses prescription? ›

About Walmart Vision Center

You can get your eyes checked, prescription updated, and shop for glasses and contacts.

How can I check my eyesight digitally? ›

Peek Acuity is a smartphone-based vision check app developed by eye experts to allow anyone to check visual acuity using only an Android smartphone. Peek Acuity helps screen and identify people who need further examination. It is not intended to replace detailed examinations from a qualified eye health professional.

How do I find my prescription on my iPhone? ›

On your iPhone, open the Health app. Tap Browse, then tap Vision Prescription.

Can my optician refuse to give me my prescription? ›

The Federal Trade Commission enforces the Eyeglass Rule. It requires eye doctors — ophthalmologists and optometrists — to give patients a copy of their prescription – whether they ask for it or not. It's the law.

Do you need a new prescription for glasses every year? ›

Eyeglass prescriptions are valid for one to two years, depending on the optometrist. Once a prescription expires, people must get a new one to get new glasses. This allows the optometrist to examine the eyes and check for vision changes.

Can you get prescription from old glasses? ›

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.

How do you calculate eye power from a prescription? ›

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.

How bad is a 1.75 eye prescription? ›

A -1.75 eyewear prescription essentially signifies that you need some additional power to see some objects that are further away. Specifically, we are talking about things like watching television or objects or people at a distance when you are driving.

Can I order glasses online without my PD? ›

Unfortunately, consumers need to have their PD to order prescription eyeglasses online, and the Eyeglass Rule does not require eye doctors to provide it with their prescription.

What does PD look like on a prescription? ›

You may see dual PD written on your prescription like this: 32/30. The first number refers to the right eye or OD measurement, and the second number refers to the left eye or OS measurement.

Do I need my PD to order glasses? ›

Before you order a pair of prescription glasses online, it's essential to have your pupillary distance (or PD) measurement. As part of your glasses prescription, PD helps ensure you to see clearly when you put on your new pair of glasses.

What's the average PD for a woman? ›

What is the average pupillary distance (PD) for females? The average PD for adult females is 62 mm, which is about 2.44 inches.

What's the lowest prescription for glasses? ›

The lowest strength is usually 1.00 diopters. Glasses go up in strength by factors of . 25 (1.50, 1.75, 2.00). The strongest glasses are 4.00 diopters.

Is 0.50 astigmatism bad? ›

Astigmatism is measured in diopters. A perfect eye with no astigmatism has 0 diopters. Most people have between 0.5 to 0.75 diopters of astigmatism. People with a measurement of 1.5 or more typically need contacts or eyeglasses to have clear vision.

Is 0.50 eye power normal? ›

Mild: -0.50 to -3. Moderate: -3.25 to -5.00. High: -5.25 to -10. Extreme: greater than-10.

What does 0.25 eye power mean? ›

The amount of astigmatism (visual distortion) that is caused by an irregularly shaped cornea. If this box is empty, it means that there is no astigmatism and your eyes are perfectly spherical. A low number like 0.25 means your eyes are not quite round and a higher number like 3.00 means your eyes are quite oval.

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 much eye power is normal? ›

Having 20/20 vision means you have normal or average, vision. Some people have vision that's better than 20/20, like 20/15 vision or 20/10 vision. This means that you can see something 20 feet away (like a line on an eye chart) that most people can see when they're 15 feet away (20/15) or 10 feet away (20/10).

What is the highest number for glasses? ›

Typical SPH numbers range between 0.00 and +/- 20.00. The SPH number on a glasses prescription is listed as a positive (+) or negative (-) number. A negative number means that the lens is correcting for nearsightedness, while a positive number indicates a prescription for farsightedness.

How bad is 2.00 eye prescription? ›

If your number is between -0.25 and -2.00, you have mild nearsightedness. If your number is between -2.25 and -5.00, you have moderate nearsightedness. If your number is lower than -5.00, you have high nearsightedness.

What are numbered glasses called? ›

Glasses prescriptions are quoted in 'Diopters'. A diopter is 1/focal length in meters. In other words, a 3.00 D lens focuses at 1/3 meters (33 cm).

Can you ask for a copy of your glasses prescription? ›

Your Right to Your Prescription

Your eye care professional has to give you a copy of your prescription — whether you ask for it or not. It's the law. For glasses, they must give you a copy after you get an eye exam.

How can I check my eyesight at home? ›

How to Do an At-Home Eye Test
  1. Print or purchase a vision chart. ...
  2. Tape the chart on a wall. ...
  3. Place your child's chair ten feet away from the chart.
  4. Ask your child to cover one of his or her eyes. ...
  5. Light the vision chart. ...
  6. Have your child read each line of the chart. ...
  7. Repeat the process with your child's other eye covered.
Apr 22, 2020


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