Click on this to go to a large format PDF file of the same image that is clearer.
This is my explanation as to why some Siamese cats are cross-eyed or at least it is possibly part of the reason. Crossed-eyes are fairly common amongst Siamese cats. You’ll also see it random bred cats too but some people treat the condition as a normal part of the anatomy of this cat breed. That is incorrect because breeders are breeding it out. You’ll probably see it much more in Thailand together with the Siamese kinked tail that has been bred out in the West. At one stage the kinked tail was as common as the cross-eyed gaze for this famous cat breed.
The condition is inherited. It is a genetically based condition. Robinson’s Genetics¹ say that the albinism gene has “other effects” on the Siamese cat. What they mean is; effects other than the coat pattern and color with which we are so familiar.
They go on to state that the albinism allele² causes a disruption in the visual pathway “preventing these cats from having full binocular vision”. I disagree that the Siamese cat does not have full binocular vision, by the way. They further state that Siamese cats “neurologically compensate” for this anatomical anomaly. In my view, we see the effects of the compensation in the crossed-eyes, also called a squint. The technical term for misaligned eyes is “strabismus”. The cross-eyed cat has horizontal strabismus as far as I am aware.
A study³ concluded that the brain of one of the extremely popular white tigers that we see in zoos (and which are sadly highly inbred) showed an abnormality of the visual pathway similar to the “abnormalities that are associated with albinism in many other mammals”. The authors state that:
There is a close relationship between the reduced pigment formation, the pathway abnormality, and strabismus.
The image on this page explains more behind my conclusions that reduced pigment formation (of melanin) due to the presence of the albinism gene causes the misrouting of the optic nerve.
I can’t, at the moment, explain why only some Siamese cats have a squint. There is perhaps more going on with respect to genetics than stated, I suspect. Or it may be that some cats just compensate without showing a squint and some cats just grow out of it (correct it as stated).
Notes:
- Robinson’s Genetics for Cat Breeders and Veterinarians page 169. The quote in the image is from this book too.
- Allele: one of two or more versions of a gene.
- Ref: Genetic Abnormality of the Visual Pathways in a “White” Tiger
I have a flame point Siamese will the cross eye make him blind or no
Hi Brianna. His eyesight is fine. The Siamese brain compensates for the faulty wiring of the optic nerve. He won’t be blind. Flame points are gorgeous and quite rare.
Gorgeous, affectionate, and all too short-lived. I blame mine’s short life (only 8 years) on the indiscriminate inbreeding that produced him for a shopping mall’s pet store. No, I hadn’t bought him there; one of my husband’s less acceptable friends did, couldn’t stand the kitten’s lonely yeowling when everyone closed their bedroom doors at night, and gave it to me instead of the SPCA.
You are kind hearted. I agree about inbreeding and your cat’s short life. I believe that modern Siamese have immune issues because of inbreeding to create the extreme appearance. Thanks for commenting.
I had no idea. Very good info to understand. thanks!
Pleasure Dan. I took me ages to figure it out and it still might be wrong 😉
The kinked tail is also not desirable in the Cat Show world- breeders also have worked hard to eliminate the kink.
But according to legend the kink had a purpose, since Siamese cats with kinks in their tales became palace guards, the purpose of the kink was to hold the royalty’s priceless jeweled rings. I hear tell also that the reason Siamese cats have crossed eyes, was because guarding the palaces required such concentration that their eyes crossed.
So many legends… but happy that these odd “features” are being bred out of these gorgeous cats.
Thankfully there are some very careful, reputable breeders who have been working very hard and carefully in their breeding programs to end crossed eyes in the Siamese breed. Crossed eyes in Siamese is serious enough that the Cat Fanciers and other governing organizations in the USA list it as a reason to disqualify the cat in competition.
Thanks for this information- extremely interesting.
Thanks Jo. Breeders have ironed out these Siamese defects. I wonder if they should have kept the kinked tail though. The tail is quite a feature in cats and the American Ringtail is built around the tail.
So even though the paths cross they make a sensible image out of what they are registering? Sounds like if not it could be totaly debilitating.
Yes, they do compensate and see normally. Well, that is what people believe. I suppose a cat’s behavior indicates normal sight although cats are very good at using other senses.
No one else has said what I have said on this page and it could be wrong but I don’t think it is.
I spent a lot of time researching this and there is nothing really conclusive regarding cats. I had to research wider and look at other mammals for answers.