You can find your eye prescription online through a few different routes: scanning your existing glasses with a smartphone app, taking an online vision test, or simply requesting your records from a previous eye doctor. Each method has different levels of accuracy, cost, and limitations, so the right choice depends on your age, eye health, and how recently you had a full exam.
Request Your Prescription From a Previous Provider
The simplest option is one many people overlook. If you’ve had an eye exam in the past one to two years, your eye doctor is legally required to give you a copy of your prescription. You can usually call the office, and many practices now offer patient portals where you can log in and download it directly. In the U.S., the FTC’s Eyeglass Rule guarantees your right to receive your prescription immediately after an exam, at no extra charge, whether you ask for it or not.
Keep in mind that eyeglass prescriptions typically expire after one to two years depending on your state. If yours is still valid, this is the fastest and most reliable way to get the numbers you need to order glasses or contacts online.
Scan Your Current Glasses With an App
Smartphone apps can read the prescription built into your existing lenses. The myRx Lens Scanner, for example, uses your phone’s camera to analyze the curvature of your lenses and extract the prescription parameters in under 10 minutes. The app walks you through the process with video and audio prompts.
This approach works well if you already own glasses and just need to reorder. But it has clear boundaries. The myRx scanner, which is FDA and CE listed, only works with single vision lenses in a specific range: roughly negative 6.00 to positive 3.00, with astigmatism correction below negative 2.50. If you wear progressive lenses, bifocals, or have a strong prescription outside that range, these apps won’t give you accurate results.
Take an Online Vision Test
Online vision tests let you measure your prescription from home using your computer or phone screen. Services like 1-800 Contacts’ ExpressExam charge around $20, compared to the roughly $150 average for an in-office exam without insurance. The process typically involves reading letters or identifying symbols on your screen from a set distance, sometimes while wearing your current glasses.
A pilot study at the Illinois College of Optometry compared remote refraction tests to traditional in-person exams across 60 eyes. The results were encouraging: 90% of the prescriptions matched within clinically acceptable margins (plus or minus 0.50 diopters for both the spherical and cylindrical components). There was no statistically significant difference between the two methods for any measured parameter. However, 10% of eyes were slightly over-corrected in the remote exam, meaning the test pushed toward a stronger prescription than needed. Four of those six eyes were farsighted, suggesting remote tests may be less reliable for people with hyperopia.
Visibly (formerly Opternative) is one company that holds FDA clearance for its remote refraction technology. After you complete the test, a licensed eye doctor reviews your results and issues the prescription, which you can then use to buy glasses anywhere.
Who Can Use Online Vision Tests
Online tests aren’t designed for everyone. The American Academy of Ophthalmology recommends limiting them to healthy adults between 18 and 39 who already have a mild to moderate prescription and no symptoms of eye disease. They work best as a way to update an existing prescription, not as a first-time exam.
You should skip online testing and see an eye doctor in person if any of the following apply to you:
- You have diabetes or a family history of glaucoma
- You have a high or irregular prescription
- You haven’t had a comprehensive eye exam recently
- You’re under 18 or over 39
- You’re experiencing new symptoms like blurry vision, floaters, or eye pain
Some states also impose restrictions on telehealth-based eye exams. Delaware, for instance, requires that a provider-patient relationship include thorough identity verification, informed consent, and a diagnosis established through accepted medical practices, which some regulators interpret as requiring an initial in-person visit. Rules vary by state, and some online services will tell you at the start whether they operate in your area.
What Online Tests Cannot Detect
An online vision test measures one thing: how well your eyes focus light, which determines your glasses prescription. A comprehensive in-person exam checks far more. Your eye doctor dilates your pupils to inspect the retina, optic nerve, and the blood vessel layer behind it. They use a slit lamp to examine the cornea, iris, and lens for damage or disease. A tonometer measures the pressure inside your eye to screen for glaucoma. Separate tests check your peripheral vision, color vision, and how well your eye muscles coordinate.
These screenings catch conditions that don’t affect your day-to-day vision until they’ve already progressed. Glaucoma, diabetic retinopathy, and macular degeneration can all develop silently for years. An online refraction test will never flag them. So even if you use online tools to update your prescription between visits, periodic comprehensive exams remain important for protecting your long-term eye health.
Getting the Most Accurate Results at Home
If you decide to take an online test, small details affect accuracy. Most services require a computer or laptop with a screen at least 10 inches across, since phone screens can introduce measurement errors. You’ll typically need to stand a specific distance from the screen, often around 10 feet, so a room with enough space matters. Good, even lighting helps too. Dim rooms or glare on the screen can throw off your responses.
Have your current glasses or contacts on hand, since many tests ask you to wear them during part of the process. Follow the distance and positioning instructions exactly. The 10% error rate seen in clinical comparisons likely reflects, at least in part, less controlled conditions at home versus a standardized clinic setting. Taking the test in a well-lit room, at the correct distance, and without rushing will give you the best shot at an accurate result.