If your lovely pet has eyes of different colors – you are very lucky! These adorable cats are carriers of the feline form of a condition known as complete heterochromia. Heterochromia in cats is a genetic abnormality and is most often observed in white cats. This condition is also normal for some rare breeds.
The cat’s eyes are significantly larger compared to the size of its head. This is actually a key feature of all nocturnal animals, as well as the vertical structure of the pupils. Actual eyeballs are placed in bony cavities called orbits. The white part of the eye is called the sclera, and it is covered with a thin membrane called the conjunctiva. The conjunctiva closes the eyelids. Before the eyes – the transparent cornea of the dome. The cornea protects the eyes and transmits light. The round colored area of the eye is the iris of the eye.
Cats are not very good at distinguishing small details, but the theory that cats see the world in black and white is considered incorrect. Interestingly, cats have a third eyelid, which can be seen when a cat is happy or sick.
Iris in domestic cats can vary in pigmentation from blue and green to yellow and brown. Sometimes the color of the eyes is associated with the color of the coat or breed. For example, Siamese cats always have blue eyes. It is generally believed that purebred cats tend to tend to have brighter and more distinct eye pigmentations due to selective breeding.
How do eyes get their color?
Eye pigment is produced by pigment-producing cells called melanocytes, which are present in the iris. The exact color and its intensity will depend on the number and activity of melanocytes in the iris. If there are no melanocytes, the eye will be blue. A low content of melanocytes leads to a green color, and a high content of melanocytes creates an orange (sand, brown) color. If melanocytes are less active, the intensity of this color will be lighter and vice versa. The activity of melanocytes is determined genetically. Several genes in different places of the chromosomes control the pigmentation of the iris.
Heterochromia in cats
Different eye colors, or heterochromia iridum, can be genetic, congenital or acquired. This condition is most common among white cats, but can occur in all other cats that also carry a white spot gene.
Reason for strange eyes
Multi-colored eyes can be inherited from parents (genetically) or acquired due to certain diseases, injuries and medications. Acquired multi-colored eyes cannot be inherited by kittens. However, most often, strange eyes are congenital.
How are congenital multi-colored eyes made?
During development, stem cells migrate to another part of the body, where they differentiate into specialized cell types. Some of them migrate through the embryo and stop in the eye, where they later become melanocytes. Under certain conditions, melanocytes cannot get into one of the eyes. This leads to the fact that one eye has melanocytes that give it pigmentation (green, amber or brown), while the other eye remains blue due to a lack of melanocyte.
Usually this situation occurs in monophonic white cats or cats with white spots. The dominant white gene (the gene that makes cats completely white) and the white spot gene sometimes interfere with the migration of melanocytes into one of the eyes. This condition is rare in cats that do not have these two genes. In non-white cats, multi-colored eyes are often the result of differently developed eyes in the fetus. These congenital strange eyes are hereditary and can be transmitted to cat kittens. This applies to such cat breeds as:
- Turkish van
- Turkish Angora
- kao mani;
- British Shorthair;
- subspecies of the Scottish cat.
It is in the listed breeds that multi-colored eyes are most often found. For example, Turkish Van and Angora inherit multi-colored eyes from generation to generation. Most often, such cats have white coat, one eye is blue, and the second is yellow-copper. Such kittens are suitable for owners who want real unique favorites.
Strange eyes and deafness
Deafness in white cats seems to be related to the white spot gene and the dominant white gene. More common in cats with blue eyes or with heterochromia. As experts explain, this is due to the fact that the white gene can sometimes cause degradation of the cochlea without disturbing the migration of melanocytes into one or both eyes. The cochlea is the part of the inner ear that is involved in hearing. This leads to permanent deafness in one or both ears.
Multi-colored eyes can be found in completely different breeds. Heterochromia is a normal deviation because such cats are no different from the rest. If your cat with colored eyes is deaf, when properly maintained and cared for, it will give you the same love and devotion as ordinary cats.