Contrast Sensitivity Test — Check Your Vision Contrast Sensitivity
This vision contrast sensitivity test shows letters that fade step by step, in the style of a Pelli-Robson chart. Keep picking the letter you see — your score is the faintest level you can still read.
Set screen brightness to a comfortable, normal level, then start.
What contrast sensitivity means
Contrast sensitivity is your ability to distinguish an object from its background — the skill you use spotting a pedestrian at dusk or reading grey text on a grey page. It's a different dimension of vision from the sharpness measured by avisual acuity testand from the hue discrimination measured by acolor blindness test, which is why clinics test it separately.
How this test works
Clinical charts like Pelli-Robson (and the MARS test) show large letters whose contrast drops in fixed logarithmic steps; your score is the faintest triplet you can read. This online version follows the same idea: each level lowers the letter's contrast against the grey background by about 0.15 log units, and two correct picks advance you. Screens can't be perfectly calibrated, so treat your result as a relative benchmark — useful for tracking change on the same screen, not as a clinical logCS value.
Frequently asked questions
What is a contrast sensitivity test?
A contrast sensitivity test measures how faint a pattern can get before you can no longer distinguish it from its background. Instead of shrinking letters like an eye chart, the letters stay large but fade step by step until they vanish into the background.
How is contrast sensitivity different from visual acuity or color blindness?
Visual acuity measures the finest detail you can resolve at full contrast; color blindness tests measure hue discrimination; contrast sensitivity measures how well you separate an object from its background — like spotting a grey car in fog. You can have perfect 6/6 acuity and still have reduced contrast sensitivity.
What can cause reduced contrast sensitivity?
Common causes include early cataracts, glaucoma, diabetic eye changes, optic nerve conditions and refractive surgery side effects. Everyday factors like a dirty windscreen effect — smudged glasses or a dim screen — also lower measured results.
Is low contrast sensitivity a sign of an eye condition?
It can be, especially if it appears while normal acuity is preserved — some conditions reduce contrast sensitivity before they affect an eye chart score. A low result on this screening is a reason to get a clinical exam, not a diagnosis by itself.
How this test works: everything runs and is timed locally in your browser, and results depend on your device and conditions. Scores are for casual benchmarking and entertainment — not a clinical, medical or diagnostic measurement.