One of the most striking physical characteristic of a Siamese cat is the rich blue eyes. In order for a Siamese to be registered and shown, the cat must have blue eyes. Occasionally, a Siamese kitten is born with different coloured eyes; in this case, the cat cannot be registered or shown. Unfortunately, Siamese can be prone to eye problems. Breeds based heavily on Siamese ancestry such as the Balinese are also prone to these eye problems.
The most common eye problem in Siamese is that of crossed eyes or strabismus. This is an inherited neurological condition from some of the first Siamese sent to America. Some of those specimens had crossed eyes. In the early 20th century in America, crossed eyes were considered a normal trait of Siamese cats. Cross-eyed cats cannot see well.
Rare Crossed Eyes
According to "Cat Owner's Home Veterinary Handbook," Siamese and breeds related to the Siamese can have a rare form of strabismus that is not caused by genetics, but is caused by a paralysis of the eye muscles. The cause of this is usually a brain tumour or nerve damage. This can happen to other breeds of cat, but seems to occur most in Siamese-type cats.
According to "ASPCA Complete Guide to Cats," Siamese are prone to a condition called nystagmus, also known as quivering eyes. This causes the cat's eyes to jerk back and forth as if they were watching a tennis match. In some cats, this movement is slight, giving the appearance the eyes are quivering. However, this happens rarely as cats with nystagmus have been removed from breeding programs.
Sometimes, Siamese kittens will be born with red eyes. They will also be born with all-white or cream coats. Siamese have the albino gene, which is seen most in kittens under one month old. By the time the kittens are a month old, they not only have their adult colouration, but the eyes have changed to blue.
According to "Siamese Cats," lilac-point Siamese are more prone to developing conjunctivitis (irritated eyes) than other colours of Siamese. Even tobacco smoke can trigger symptoms lilac-point Siamese that has a history of conjunctivitis.