Hold a real ruler against the display. Adjust the black bar until it measures exactly 50 mm (5 cm). Keep browser zoom unchanged after calibration.
Sit in good, even lighting. Measure 1 meter from your eyes to the screen and cover the eye you are not testing without pressing on it.
Your answers stay in this browser and are not sent or stored.
You can also use the keyboard arrow keys. Guess if you are unsure; do not move closer.
Method
The E is scaled from your 50 mm calibration and the 1-meter viewing distance. Each level contains five randomly rotated symbols. Passing four or more advances to a smaller symbol.
A result such as 20/40 is a screening estimate, not a prescription. Screen calibration, viewing distance, lighting, display quality, fatigue, and guessing can all affect it.
Comparison
Run the check once with your glasses in their normal position, then repeat with them moved forward. Keep the same eye, screen, lighting, head position, and measured distance.
One line of difference can happen through normal test variability. A result that repeats across several runs is more meaningful, but should still be discussed with an eye-care professional.
Private by design
The screening runs inside your browser. Your eye choice, answers, glasses position, and result are never uploaded to Vision Checker.
Read the full privacy policyBook a routine professional eye examination if you notice a persistent change, one eye performs differently from the other, your glasses no longer feel right, or the result concerns you.
Seek urgent medical care for sudden vision loss, a curtain or shadow in your vision, new flashes with many floaters, severe eye pain, eye injury, or sudden double vision.
Good to know
No. It estimates distance visual acuity under your current conditions. A prescription requires a professional refraction and eye examination.
It means you identified at 20 feet what a person with standard 20/20 acuity could identify at 40 feet, expressed here as an approximate screening equivalent. It does not explain why vision is reduced.
Yes, if the screen is large enough to display the biggest symbols and you can keep it stationary at exactly 1 meter. Calibrate the screen with a ruler first.
Testing separately can reveal a difference that both eyes together may mask. Cover the other eye gently without applying pressure.
Small changes can come from guessing, fatigue, dry eyes, lighting, viewing distance, or calibration. Compare repeated runs made under the same conditions rather than relying on a single result.
No. The test runs entirely in your browser. Vision Checker does not upload or save your answers or screening result.
