The Other Axis

CONTRAST
SENSITIVITY
TEST

Eye charts test sharpness with high-contrast black letters. But real life is full of faint differences — fog, dusk, a face across a dim room. This test fades a letter toward the background until it nearly vanishes, and finds the faintest one you can still read. It's a different axis of vision entirely, and often the first to slip.

How it works

1
Name the letter
One of six shows faintly. Tap which one — or "Can't tell" if it's gone.
2
It fades as you succeed
Get it right and the next is fainter; miss and it strengthens. This finds your edge.
3
Sit back a little
Arm's length, screen brightness up. ~24 trials.
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TRIAL 1 / 24—

Which letter do you see?

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Results

YOUR
CONTRAST
FLOOR

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Note
Contrast sensitivity is a genuinely useful axis — it can dip before sharpness does in some eye conditions. But your screen's brightness and gamma are unknown and uncalibrated, so this is not a Pelli-Robson score and can't be compared between devices. It's most meaningful tracked against your own results on the same screen. A real contrast test is done by an eye clinic. Not a diagnosis.