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Tritanopia Test

A blue-yellow color vision test. It screens for tritanopia and tritanomaly using plates that are hidden only from people with reduced blue-cone sensitivity.

Important: turn off Night Shift, Night Light, True Tone, Eye Comfort and any blue-light filter before starting. These settings remove blue light and can make anyone fail this test.


What number do you see?

Each plate hides a number made of colored dots. Type the number you see, or tap “I can’t see a number”.

8 to 9 plates · about 1 minute

For accurate results
  • Turn screen brightness up and switch off Night Shift, True Tone, Night Light, blue-light filters and any color-adjusting apps or extensions.
  • Use a phone, tablet or monitor in normal indoor light, not in direct sunlight.
  • Wear your usual glasses or contacts, but not tinted or color-correcting lenses.
  • Don’t zoom in or stare. Answer with your first impression within a few seconds.

Keyboard: 0–9 type the number · Enter next · Backspace delete · N or Esc can’t see a number

How the tritan plates work

Every plate hides a number whose color differs from the background only in how strongly it excites the blue-sensitive cones. People with normal color vision see violet or blue digits on an olive or grey background. People missing blue-cone function see a uniform field. Five contrast levels let us estimate how strong a blue-yellow deficiency is.

Learn more about the two blue-yellow types: tritanomaly (blue cones present but shifted) and tritanopia (blue-cone function missing).

A tritanopia and tritanomaly test in one

This blue-yellow color blind test covers both tritan types. Tritanopia means blue-cone function is missing, so even the strongest plates look blank. Tritanomaly means the blue cones are present but weaker, so only the subtler plates disappear. Because the plates come in five strengths, the same test works as a tritanomaly test and a tritanopia test.

Why a separate blue-yellow test?

Most color blind tests, including the classic printed Ishihara plates, are designed for red-green deficiency and don’t check the blue-sensitive cones at all. Passing one of those says nothing about blue-yellow color vision. Ourmain color blind test includes two tritan plates; this page adds the full set of five levels plus a repeat of the subtlest one.

Reading your result

  • No blue-yellow deficiency detected: you saw the number on every plate.
  • Mild: you missed only the subtlest plates. Check your screen settings and try again, because a warm display mode or low brightness can cause this on its own.
  • Moderate to strong: you missed several levels with all filters off. This fits tritanomaly or tritanopia.

The results page shows each plate with your answer and what typical color vision sees. To see what a tritan result means for everyday colors, open the simulator in tritanopia mode.

Inherited or acquired?

Red-green color blindness is almost always inherited, but blue-yellow defects are often acquired through eye disease, diabetes, ageing of the lens, or medication. If this test suggests a blue-yellow problem and you haven’t had one before, please see an eye doctor.

Note: this is a screening, not a diagnosis. Online tests can’t control your screen’s colors or brightness, so confirm any result with an eye care professional. Medical disclaimer · How the test works

More color vision tests

Color blind testFull screening: red-green and blue-yellow, with type and severity.Red-green color blind testDeeper check for protan and deutan types.Color blind test for kidsShapes instead of numbers, for children who can’t read digits yet.Reverse color blind testHidden-figure plates that color blind people can see more easily.Color blind simulatorSee any photo the way people with color blindness see it.

Frequently asked questions

What is tritanopia?

Tritanopia is a rare blue-yellow color blindness in which the blue-sensitive (S) cones are missing or not working. Blue and green look alike, and yellow can look pink or grey. Tritanomaly is the milder form.

How rare is tritanopia?

Inherited tritan defects are rare, with estimates from about 1 in 10,000 to 1 in 50,000 people. Unlike red-green color blindness, it affects men and women equally.

Can blue-yellow color blindness develop later in life?

Yes. Blue-yellow changes are the most common acquired color vision defects and can be caused by glaucoma, diabetic eye disease, cataract, other eye or nerve conditions, and some medications. A new or worsening problem should be checked by an eye doctor.

Why do screen settings matter so much for this test?

Night Shift, Night Light, True Tone and blue-light filters reduce the blue light from your screen, which is exactly what this test measures. Turn them off before testing, or you may get a false result.

I passed a red-green test but failed this one. Is that possible?

Yes. Red-green and blue-yellow color vision depend on different cones, so one can be typical while the other is not. Most popular plate tests only check red-green. If you failed this test with all screen filters off, and especially if your color vision seems to have changed, see an eye doctor.

Is blue-yellow color blindness the same as blue-green color blindness?

People often call it either. Tritan defects affect the blue-sensitive cones, so blue can be confused with green and yellow with pink or light grey. Tests sold as a “blue-green” or “blue color blind test” are screening the same tritan cones as this one.