Change of Eye Color in a Siamese Cat

Sapphire blue eyes of siamese catSiamese cats are meant to have blue eyes. The blue eye colour is linked to the coat, which is the Siamese pattern or colourpoint. The CFA Siamese breed standard refers to the shape of the eyes and the fact that they should not be crossed – a common “defect” in Siamese cats and that they should be vivid blue. A Siamese show cat will be disqualified if he does not have blue eyes. Disqualification also occurs if the cat has white toes and/or feet. White toes/feet would occur if the white spotting gene were present.

All kittens, of any cat breed or no breed at all, are born with blue eyes and this is because the pigmentation in the iris is not fully formed which leaves the colour in the eyes to be created by the physical nature of what is called the refraction of light as it impinges upon the eye. There is a page on that on this website which explains how that works.

The Siamese is typical in that the kitten is born devoid of pigment and begins to form pigment within a few days. Accordingly, the Siamese cat will start off with blue eyes but they will change in colour as the pigment develops under the direction of the relevant gene. Normally in the Siamese, the colour of the eyes will start forming to blue after about 6 weeks.

Siamese cat without blue eyes

Siamese cat without blue eyes? This is a genuine Siamese cat in Siam (Thailand).

It would seem to me that on some occasions, at this stage, a Siamese cat may develop odd-eyes (heterochromia iridum) or the wrong colour eyes per the breed standard. One eye may remain blue and the other may turn yellow. Normally, odd-eyes will be seen in a cat that carries the white spotting gene or the dominant white gene. However, the Siamese cat is a Siamese cat because it carries a specific gene and not as far as I’m aware the white spotting gene.

On that basis, when people talk about a change of eye colour in a Siamese cat, they may be referring to a Siamese cat which is not purebred. Sometimes you see Siamese-type cats with the odd fleck of white caused by the white spotting gene. These cats may have odd-eye color or the “wrong” eye color. I am happy be corrected or my post added to by anyone.

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Change of Eye Color in a Siamese Cat — 17 Comments

  1. Interesting.
    So, a purebred siamese will never have white feet or anything other than blue eyes. It bothers me that a purebred with crossed eyes is considered flawed. The cat is still siamese.
    I don’t like the word flawed. We don’t call a crossed eyed human flawed.

    • Agreed. The cat fancy removed the cross-eyed look and the kinked tail (both common in real Siamese). They also “refined” the cat by making it more slender (skinny actually). The Siamese cannot have any white blobs anywhere. The coat is purely pointed and the eyes blue.

  2. The specific coat and blue eyes of the Siamese are caused by one of the 5 forms of albinism not the W or S genes. The S gene is sometimes found in chocolate point Siamese and probably originated from Chines Whites which carry that gene. This may be the origin of occasional white markings in otherwise normal Siamese, but other out-crossing may also be responsible. A pure-bred Siamese should not carry the S gene. The Siamese blue eyes are not linked to deafness but to producing a squint.

    I am not sure what is meant by change of eye colour in a Siamese cat. The quote contained in the article ” cat eye colour” (above link “colour of the eyes) does not refer to Siamese cats. They are born blue and continue to be blue, albeit a different tone.

  3. I have a 5yr male Siamese (pedigree/very good lines) and his eyes have always been a vibrant blue. They have just started to go a dull blue with a hint of green in one. His behaviour is quite normal. Any suggestions why the colour might change?

    • I am not sure Fiona. My guess is that it is age related. What little pigmentation there is, may be altering with age. Note: Blue eyes are largely caused by the light entering the eye being refracted rather than looking blue because of blue pigment in the iris. There may be a hidden green eye gene which is becoming more noticeable as the cat becomes older (a wild guess!).

      They could possibly be a change in the eye which is causing the color change. I could not find any health issues associated with the Siamese which supports that idea.

      This page comprehensively lists Siamese cat health problems:

      Thanks for visiting and commenting.

  4. I have what i think is a Siamese and his right eye has changed from blue to yellow. He does have white feet. Would he be considered Siamese?

    • Hi Jerry. He is not a true Siamese per the Siamese breed standard although your cat has many Siamese traits. He carries the white spotting gene which is causing the white feet. In competition the yellow eye would result in disqualification.

      I would consider him as Siamese-like or a Siamese mix perhaps but not a true Siamese. But it depends on one’s own rules. Under the breed Standard he is not a Siamese it seems to me.

      Thanks for visiting and asking. It does not matter. He is a lovely cat and just as good if not better than a purebred Siamese who relatively often have health problems.

  5. my cat is probably around one year old, it was told to me by vet. he is not pure Siamese, his eyes are looking very light blue, an lids kinda pink, pls help ????????

  6. My simese cats eyes are crystal blue but change color as she plays red when she is in play mide with her toy mice and black when she gets mad

    • Both are pointed but the Himalayan is long haired and looks like a flat faced Persian while the Siamese is shorthaired, has a long face and is slender. The Himmie is much more rounded and compact looking. You can see full descriptions of both cats on this site. Go to the menu and find the breed there.

      They are very different cats and that applies to character too. The Siamese is vocal and likes interaction with people while the Himmie has Persian cat traits: somewhat static and decorative but can be nervous. Hope this helps Rico.

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