Contrast Sensitivity Test
Visual acuity tells you how small you can see; contrast sensitivity tells you how faint — and it is often the better predictor of real-world vision in fog, at dusk or on a washed-out display. Each trial hides a soft striped patch (a Gabor patch, the standard stimulus of vision science) in one of four gray boxes; click the box where you see it. Answer correctly twice in a row and the contrast drops; miss and it rises — a classic two-down-one-up staircase that converges on the contrast you can detect about 70% of the time. After eight reversals (or 40 trials) the test ends and reports your threshold as a Michelson contrast percentage plus a sensitivity score. Your best result is kept on this device. It is a screen-dependent estimate, not an eye exam.
Runs 100% in your browser — your puzzles never leave your device.
Read the full guide to this tool
Notes
- Michelson contrast is (max − min) / (max + min) of the pattern’s luminance: 100% is black-on-white stripes, and thresholds below 1% are common for healthy vision on a decent screen.
- The two-down-one-up staircase converges on the roughly 71%-correct point of your psychometric function; the reported threshold is the average of the last several reversal points.
- Everything about your setup shifts the number — screen brightness, gamma, ambient light, viewing distance, even a dirty screen — so treat this as a relative self-check, never a medical measurement.
- Runs 100% in your browser — your words and puzzles never leave your device.
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