Hardware diagnostic ยท no ranking
Color Blindness Test
Fourteen plates. Type what you see, or say that you see nothing.
Before you start
Run the test and your reading appears here.
Plate 1 of 14
Why this reports a type instead of a percentile
Colour vision deficiency is not a spectrum that everyone sits somewhere on. Around 92 percent of people have normal colour vision and get essentially every plate right. Reporting your rank in that population would tell you nothing: you would either be at the top with everyone else or far outside it.
What is worth knowing is which plates you missed. Red-green deficiency and blue-yellow deficiency produce different miss patterns, and the pattern is the diagnostic signal. So this test reports the type the errors point to, and it says plainly when the pattern is not clear enough to call.
The three patterns this screens for
Protan, a red weakness. Reds appear darker and duller, and red against black can vanish entirely. Affects roughly 1 percent of men.
Deutan, a green weakness. By far the most common form, around 5 percent of men. Reds and greens both drift toward a muddy yellow-brown. Many people with mild deutan deficiency reach adulthood without knowing.
Tritan, a blue-yellow weakness. Rare, roughly 1 in 10,000, and unlike the other two it is not sex-linked. It can also be acquired later in life through eye disease or medication, which makes a new tritan result more worth following up than a lifelong red-green one.
What a screening test cannot do
Ishihara-style plates were designed for print under standard illumination. Your screen is not that. Panel calibration, brightness, colour profile, ambient light, and any night-shift or blue-light filter all shift the colours away from the intended values, and every one of those shifts can create a false result in either direction.
A screening test also cannot grade severity. Clinical assessment uses an anomaloscope or an arrangement test like the Farnsworth D-15 to establish how strong a deficiency is, which is the part that matters for occupational requirements.
Turn off any colour filter, set brightness to normal, and view in even lighting. If the result surprises you, repeat it on a different screen before believing it.
Questions
- How accurate is an online colour blindness test?
- It is good at flagging a strong red-green deficiency and unreliable for anything mild. Screen calibration, ambient light, and blue-light filters all move the colours. Use it as a prompt to get properly tested, never as a conclusion.
- I got everything right but I still confuse some colours. Why?
- Ishihara plates target red-green confusion specifically and are insensitive to mild or blue-yellow deficiency. They also cannot detect the acquired forms that develop with eye disease. Normal plates plus real-world difficulty is a good reason for a clinical test.
- Can colour blindness be corrected?
- No. Tinted lenses can increase the contrast between colours that you confuse, which some people find genuinely useful, but they do not restore the missing cone response. The underlying deficiency is unchanged.
- Why do more men have it than women?
- The genes for red and green photopigments sit on the X chromosome. A man has one X, so a single affected copy produces the deficiency. A woman has two, and the second copy usually compensates. This is why red-green deficiency affects about 8 percent of men and about 0.5 percent of women.