Can an online vision test replace an eye exam?

No. It can only screen distance visual acuity. A comprehensive eye exam checks eye health, refraction, pressure, retina, visual field and other findings that a screen cannot evaluate.

What does 20/20 mean?

20/20 is Snellen notation. It means you can read at 20 feet what a person with standard visual acuity is expected to read at 20 feet.

Why should I test each eye separately?

Testing both eyes together can hide a problem in one eye. Separate right-eye and left-eye results are more useful for deciding whether to schedule an exam.

Can this give me a glasses prescription?

No. A prescription requires a refraction and clinical judgment from an eye-care professional.

Online Vision Test

Run a screen-based Snellen-style visual acuity screening check for each eye, with distance and screen-size calibration caveats.

This is a visual acuity screening check. Test one eye at a time without pressing on the covered eye. A screen is not a calibrated clinical chart, and the result is not a prescription or an eye exam replacement.

Viewing distance, feet

Screen diagonal, inches

Eye being checked

Select the smallest row you can read clearly

What the online vision test checks

This page is a screen-based visual acuity screening check. It uses Snellen-style rows to estimate the smallest line you can read with each eye at the chosen distance.

Screening only

An online vision test is not a diagnosis, prescription, refraction or comprehensive eye exam. It cannot evaluate eye pressure, retina health, peripheral vision, eye disease or whether glasses or contacts are appropriate.

How to use the chart

Test the right and left eye separately, covering the other eye without pressing on it.
Use a laptop or monitor when possible, keep browser zoom at 100%, and avoid glare.
Enter the viewing distance and screen diagonal so the chart can scale consistently.
Choose the lowest line you can read with most letters correct.

V i s u a l a c u i t y = \frac{t es t d i s t an ce}{s t an d a r d d i s t an ce f or t ha t l in e}

Snellen notation compares the test distance with the distance at which a person with standard acuity can read the same line.

When to book an eye exam

Result or symptom	Next step
One eye is much worse than the other	Schedule an eye exam even if both eyes together seem acceptable.
20/30 to 20/40 screening result	Consider an optometrist or ophthalmologist visit, especially with headaches or eye strain.
20/50 or worse	Do not rely on the online result; book an in-person vision evaluation.
Sudden vision loss, flashes, new floaters, eye pain or trauma	Seek urgent medical care rather than repeating an online test.

Frequently Asked Questions

Sources and References

Calculations are based on the listed reference sources. Links open in a new tab.

Updated: June 2, 2026

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