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Tritanomaly

Tritanomaly reduces the sensitivity of the blue-sensitive (S) cones. Blues and greens, and yellows and pinks or light grays, become harder to tell apart. Unlike red-green types, it affects men and women about equally.

Tritanomaly is the milder form of tritan (blue-yellow) color blindness. The complete form is tritanopia.

Blue-yellow color vision deficiency · Last updated 2026-11-10

What does tritanomaly look like?

Illustration of fruit in a blue bowl with typical color vision: red apple, green apple, yellow lemon, orange, purple grapes, pink peach and blueberries.Typical color vision
The same fruit bowl simulated with moderate tritanomaly. Blue shifts toward teal and moves closer to green, and yellow turns pale peach. Reds and pinks are largely unchanged.Simulated moderate tritanomaly
Blue shifts toward teal and moves closer to green, and yellow turns pale peach. Reds and pinks are largely unchanged.
Nine color swatches (red, orange, yellow, green, teal, blue, purple, pink and brown) with typical vision and simulated with moderate tritanomaly.
Common colors with typical vision (top) and simulated moderate tritanomaly (bottom). Images are simulations based on the Machado, Oliveira & Fernandes (2009) model at moderate severity; real experience varies from person to person and with your screen.
  • Blue and green, and yellow and pink, can look similar.
  • Colors may look less vivid overall.
  • Dark blues can look nearly black.

Try our color blind simulator to see your own photos the way someone with a tritan deficiency might.

How common is tritanomaly?

Inherited tritan defects are rare (estimates range from about 1 in 10,000 to 1 in 50,000 people).

Everyday situations that can be tricky

  • Blue/green status lights and charts.
  • Distinguishing some fruit and plant colors.

Causes

It can be inherited (autosomal dominant, OPN1SW gene) but blue-yellow changes are also commonly acquired from eye conditions such as glaucoma, diabetic eye disease, cataract or ageing of the lens, and some medications. A new or changing blue-yellow problem should be checked by an eye doctor.

Tritanomaly vs tritanopia

Both involve the blue-sensitive (S) cones. In tritanomaly those cones work but less well, so blue-green and yellow confusions are milder. In tritanopia they are missing or not working, so blue and green, and yellow and pink, can look the same. Both affect men and women about equally.

Read more about tritanopia.

Glasses, apps and other aids

Color-enhancing glasses designed for red-green deficiencies are not intended for tritan defects. What the studies found, type by type: do color blind glasses work?

Phone and computer accessibility settings (color filters), color-identifier apps, and asking for labels or patterns on color-coded information can all help. There is currently no approved cure for inherited color blindness.

How is tritanomaly diagnosed?

Eye care professionals use plate tests (such as Ishihara or HRR plates), arrangement tests and, for a precise diagnosis, an anomaloscope. Online tests like ours can flag a likely deficiency but can’t replace a clinical test.

Take the tritanopia test

Tritanomaly FAQ

What is tritanomaly?

Tritanomaly is a blue-yellow color vision deficiency in which the blue-sensitive (S) cones work abnormally. It makes blue and green, and yellow and red or pink, harder to tell apart.

What does tritanomaly look like?

Blues look more like greens, yellows look paler or pinkish, and colors can seem less vivid. The images above simulate a moderate case.

Is there a tritanomaly test?

Our tritanopia test screens for both tritanomaly and tritanopia with blue-yellow plates at five contrast levels. Screen brightness, blue-light filters such as Night Shift and room lighting affect tritan results, so turn filters off first.

Can tritanomaly develop later in life?

Inherited tritanomaly is present from birth. Blue-yellow changes can also be acquired, for example with glaucoma, diabetic eye disease, cataract or some medications. A new or changing color problem should be checked by an eye doctor.

Is tritanomaly rare?

Yes. MedlinePlus estimates that inherited blue-yellow color vision deficiency affects fewer than 1 in 10,000 people worldwide, and it affects men and women equally.

Other types of color blindness

See all types of color blindness compared side by side, or what colorblind people see with each type.

Sources

  1. National Eye Institute. Types of color vision deficiency. nei.nih.gov
  2. MedlinePlus Genetics, U.S. National Library of Medicine. Color vision deficiency. medlineplus.gov
  3. Weitz CJ, Miyake Y, Shinzato K, et al. Human tritanopia associated with two amino acid substitutions in the blue-sensitive opsin. Am J Hum Genet. 1992;50(3):498–507. pmc.ncbi.nlm.nih.gov
  4. Simunovic MP. Colour vision deficiency. Eye. 2010;24(5):747–755. pubmed.ncbi.nlm.nih.gov
  5. Machado GM, Oliveira MM, Fernandes LAF. A physiologically-based model for simulation of color vision deficiency. IEEE TVCG. 2009;15(6):1291–1298. (Used for the simulated images.) doi.org

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

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