Free • No signup • 3 minutes • Mobile-friendly
See the faint patterns your eye chart never asks about.
A free, calibrated contrast sensitivity test. Honest science, no dark patterns, results stay on your device.
Take the testOpens the test app in this tab. Works on phone, tablet, laptop.
Three steps. About three minutes.
Curious about how your score is read? See “What does my score mean?” in the FAQ.
Contrast sensitivity isn’t acuity.
A 20/20 chart asks one question: can you read tiny, very high contrast letters? Contrast sensitivity asks the whole map — how faint a pattern you can see, across a range of pattern sizes (spatial frequencies, in cycles per degree).
The Campbell-Robson chart on the right is the classic illustration. Pattern stripes get finer left to right; contrast gets fainter top to bottom. The visible “envelope” is roughly your contrast sensitivity function — peaking near 3 cycles per degree.
We build on the same psychophysics behind the Pelli-Robson chart and the FACT grating test, but use an adaptive staircase instead of a fixed printed page — so a screen can replace the ceiling-limited chart without losing the measurement.
Conditions associated with contrast sensitivity loss.
Contrast sensitivity is a non-specific signal. A dip can have many causes — uncorrected refraction, fatigue, dry eye, lighting, or a real change in visual processing. The conditions below are commonly discussed in the research; none of them are diagnosed by this test.