Odd Eyed Cats or Hetrochromia in Cats
The eyes of a cat are one of the most attractive features that attract every human’s attraction. The stand out feature in cats is their eyes and they come in many different colors and shades. When we think of cats, it is the eyes that come first into our thoughts. Cats have blue, green or amber colored eyes, but occasionally we encounter some cats with multi-colored eyes. These odd eyed cats have one eye of one color and the other with another color. This condition is called hetrochromia. A Hetrochromia eye is not a serious condition, but a rare condition that causes the iris of both eyes to contain different colors. The technical name for this rare condition is Hetrochromia Iridis, which is a Greek name for differently colored Irises.
These cats are also called odd-eyed cats and even humans are born with cat eyes or light colored eyes with different variations. There is no need to worry if your cat is born this condition as it is not a medical condition and these cats are not at a disadvantage of any sorts. Humans have Hetrochromia like cats, although complete hetrochromia is very rare in humans. Cats with this condition are called odd eyed cats or multi-colored eyes, but humans with this condition are said to have cat eyes.
Cause of Hetrochromia
The pigment called melanin determines the color of the eyes. It is the same pigment that turns light skinned people brown when they sit under the sun and get sun tanned. The amount of melanin in the iris is usually determined by the individual’s genes. It is the white or white spotted gene that is found in some cats that causes hetrochromia in cats. This particular gene affects the coat color as the dominant white gene (W) masks any other color genes to make the cat completely white. However, the white spotted gene (S) is responsible for the tuxedo and bi-color cats.
The dominant white gene prevents the pigment melanin from reaching one eye during the development stages resulting in multi-colored eyes in certain cats. Such cats have one blue eye and the other green, brown or yellow. This condition is rarely found in cats that lack the white spotting and the dominant white gene.
A kitten’s coat color is decided in the womb and all kittens are born with blue eyes. As the kittens develop, the pigment melanin moves into the iris. Within seven and twelve weeks the color of the eyes changes in cats. During this period if no melanin moves into the iris, the cat is born with blue eyes. The side-effect of the (S) gene prevents the pigment from reaching one eye as the kitten develops, which results in this particular eye remaining blue. The other eye will change its color into brown, green or yellow.
Some particular cat breeds are more prone to multi-colored eyes. These include the Turkish Angora, Turkish Van and the Japanese Bobtail. Even other cat breeds with an S or W gene can be born with hetrochromia. Complete hetrochromia is very rare and that’s why the Turkish Angora with one blue and other amber color eyes is a national treasure. The Turkish government is working to protect and preserve these odd eyed cats.
Cause for Concern
You need to be concerned if an adult, fully grown cat develops hetrochromia. This is a medical condition as this may be due to accumulation of iron deposits or blood in the anterior of the eyes. The may be due to an inflammation. Low grade uviatis may cause the exact opposite reaction making one eye lighter than the other. If you notice any changes in your adult cat’s eyes, then it is time to take a visit to the veterinarian.
Cats with odd eyes
Odd eyed cats are extremely popular among certain cat breeds like the Turkish Angora, Turkish Van, Sphynx, Persian, Japanese Bobtail, Khao Manee and the Oriental Shorthair. More often than not, complete hetrochromia occurs in white colored cats or the cats that possesses the white spotted gene that can happen to cats of any color. The Government of Turkey along with authorities of the Ankara Zoo began the study and meticulous breeding to protect and preserve the pure white Turkish Angora breed with one blue and the other amber eyes. This program is still continuing in the country and the Turkish Angora is considered the national treasure of the country. Khao–Manee is a pure white cat breed with silver and gold eyes. In many Indonesian cultures the Khao Manee is considered extremely lucky because of its color and odd eyed features.
The Turkish folklore suggests that the eyes of the Angora must be green as a lake and blue just like the sky. In the Japanese Bobtail, the odd-eyed feature can be found in calico individuals. The rarest cat with two odd colored eyes is tortoiseshell or black.
Odd eyes and Kittens
All cats are born as blue eyed kittens and the color changes as they start growing. The difference in an odd eyed kitten may not be easily visible, but only through close inspection. Odd-eyed kittens have a different shade of blue color in each eye. The color of the odd eye varies or alters after a few months as the kittens grow in age. It may vary from blue to green to yellow or even from green to blue to yellow until it reaches the final color.
Multi-colored eyes and deafness
In cats congenital deafness is inherited and is seen in most white coated individuals. The deafness is caused due to degeneration of the auditory apparatus in the inner ear. This may affect one ear or both ears. Breeding programs have studied the relationship between the deafness in white colored cats and the multi-colored eyes. The gene that is responsible for the color white is the dominant gene termed as the (W) gene. This gene causes more than one effect, one being responsible for the white coat and also the blue eyes and deafness. While this gene causes white color coat, it also has incomplete penetrance for the blue eyes and deafness, but these two are strongly linked. This means deafness is linked with the blue eyes and white coat, but all white color cats with blue eyes are not deaf.
For a white cat with blue colored eyes or odd eyes to have a predisposition for deafness, they must have pure white color coat with not even a smudge of another color. Even a small strand of other color will reduce the likelihood of potential deafness.
Effects on odd-eyed cats
Colored cats with odd-eyed appearance will not have any effect on the cat, but the lack of melanin production that is caused due to the dominant white gene which also causes the white color coat, makes such cats more sensitive to sun. Their tendency to bear the heat goes down drastically. White colored cats should be cared for by keeping them away from sun and hot weathers. They have to stay in a cool shady place away from the bright weather. You can use sunscreen on the exposed areas and regularly lookout for any bumps or lumps or any other skin condition, which can be melanoma or skin cancer.
Red eye effect and Odd Eyes
In photographs where flash is used, the odd eyed cats show the typical red eye effect on the blue eye, but this is not the case with the other eye. This is due to the combined effect of the normal presence of a tapetum lucidum a tissue in both the eyes and lack of melanin in the blue eye. This tissue is responsible for producing eye shine in both eyes. In the non-blue eye a layer of melanin over the tissue selectively eliminates some colors of light.
The odd-eyed or multi-colored eye cats are a phenomenon. These cats are not only stunningly beautiful, but also an interesting study from the genetic point of view. For any such study to progress the breeder should have complete knowledge of the cat; inheritance of the white coat and learn about the anatomy of the eyes. Genetic mutation altered the coat color as well as the pigment that develops the color of the eyes. The dominant genes that affect the color are the dominant white and the piebald spotting.
Types of partial hetrochromia
There are two different types of partial hetrochromia found in cats, a condition in which one of both irises does contain two varied colors.
There is a section or spot of the iris, which has one different color than the rest. This section takes a shape of a slice of pizza or a piece of pie.
Central hetrochromia :
The area of the iris that is closest to the pupil is encircled by one particular color and the rest of the iris is of a different color or altogether different shade.
A cat’s eye color stabilizes only after three months of birth. A change in eye color in an adult cat is not normal and is a sign of some health issue. The uvea, the part of the eye where the pigment lies is the prime source. An inflammation of the uvea or Uveitis can change the color of the cat’s eyes drastically. Uveitis is rarely a problem on its own, it is the symptom of number of other various conditions, which require medical attention. A cat suffering from this condition will have the color of his eyes changing abruptly. The potential causes maybe physical injury, an infection due to bacteria, parasite, virus or fungus. The other reasons can be due fault in other bodily systems like BP or diabetes, Cancer or autoimmune.
Having a hetrochromia eyes in cats will not hamper your cat’s daily activity or natural instincts. Your cat can see things as clearly as any other cat without hetrochromia.