What is heterochromia: its features, causes and methods of correction

Most often we pay attention to the eyes when we meet someone. It’s not for nothing that they are called the mirror of the soul. And, of course, we immediately notice their color. Unusual, bright shades of the iris always attract attention. We are used to the fact that the left and right eyes are the same color. But it happens that they are different, for example, brown and green.

Our iris has several primary colors: brown, gray, blue, blue, green, black, olive, amber (walnut). The most common eye color on earth is brown, since its carriers are representatives of two large races that make up the main population of the planet - Negroid and Mongoloid. The rarest color of the iris is green, found in only 2% of the world's inhabitants. There are also different variations, such as turquoise or emerald. But there is another rare category of people who have eyes of different colors. These can be the following options: blue and brown, green and gray and others. This anomaly is called heterochromia, and it occurs in only 1% of the population.

What is ocular heterochromia?

Heterochromia is a different color of the iris in the left and right eyes or heterogeneous coloring of areas of the iris in one of them. Its tone is determined by the concentration and distribution of melanin in the anterior (mesodermal) layer. In the case of heterochromia of the eyes, this pigment is either lacking, or, conversely, it is present in excess.

In the vast majority of cases, this is a congenital anomaly, and only sometimes (for example, with cataracts, trauma to the visual organs, hemorrhage in the tissue of the visual organs, Fuchs syndrome and for other reasons) melanin pigmentation may be disrupted.

Acquired heterochromia can be corrected with surgery, but congenital heterochromia cannot be cured. This disease also has various forms.

What cat breeds are prone to this phenomenon?

The most common breed with this unique phenomenon is the Turkish Angora; these cats have a white color, which is also typical for animals with heterochromia. But besides this, they often experience deafness, which is also associated with changes in melatonin.

The Turkish Van breed also often has one blue eye and the other green or yellow eye. In addition, there is a frequent manifestation of heterochromia in the Japanese bobtail, sphinx, and kao mani.

Types of heterochromia of the eyes in humans

This pigmentation disorder also has several varieties that differ visually and also have different causes and consequences.

Complete heterochromia

The most common type is when a person has two evenly colored irises of different colors. The most common variations are a combination of brown and green, brown and blue. This is a congenital feature that does not pose a danger to the visual organs. With it, a person sees as well as people with the same color eyes.

Sector heterochromia (partial)

It is caused by the coloring of one of the eyes in different tones. With this form of heterochromia of the iris, there can be any number of options: in half, in quarters, there are wavy borders (a rare case). This is due to the uneven distribution of melanin during the formation of color in the first six months of life.

Heterochromia central

With this deviation, several distinct rings of different colors can be distinguished. It looks quite original, and some people do not even suspect that they have a rare anomaly of iris pigmentation, proud of their unusual eyes.

Metallosous heterochromia

A rare species caused by mechanical damage. Occurs when metal particles (bronze, copper) enter the upper layer of the iris or sclera. Such a foreign body, several microns in size, is insensitive to the eye. Over time, the iron element, being in a humid environment, begins to oxidize and leads to the formation of a pigment, usually a rusty green or light green hue. Even when the scale is removed, the phenomenon does not disappear. Typically, this type of anomaly occurs in people involved in the production of metals.


Why this condition develops is not yet fully understood. The pigment melatonin, which colors the iris, can have different meanings and quantities in the eyes of one pet, which is why it turns out that the shades of the eyes are different.

Heterochromia is usually a congenital condition and appears after birth. You've probably noticed that when a kitten's eyes open, they are always blue, and only after a few weeks the iris changes color, then it turns out that the pet's eyes are a different color.

But there are exceptions; sometimes the color changes after injury, as a result of the development of cancer, serious inflammatory processes or ophthalmological problems. Therefore, if you notice that your animal’s eye color is changing, you should visit a veterinary clinic for examination and to rule out dangerous conditions.

Also, heterochromia can be complete, when the eyes have the same shade over the entire area, or sectoral, when the color changes partially.

Experts note that there are breeds of dogs and cats in which this phenomenon is most common.

In addition, it turned out that pure white cats more often have different eyes than animals of other colors.

What can heterochromia mean for eye health?

The amount of melanin in the iris, of course, cannot in any way affect the quality of vision. But there are cases when a change in pigmentation is caused by a disease, for example, Fuchs syndrome (which can lead to the development of cataracts or glaucoma), siderosis or chalcosis (copper salts entering the iris).

If you notice a change in its color, then this is a reason to consult a doctor to find out the reasons. This fact indicates that some kind of disturbance has occurred in the functioning of the body, and this is only an indicator. With congenital heterochromia, nothing threatens the eyes.

Structure and functioning of the lens


occupies the posterior ocular chamber. It is shaped like a biconvex lens. Its anterior surface is flatter than its posterior surface. The thickness of the lens is 4-5 mm, height is about 9 mm.

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Normally, this element of the eye is transparent, since it contains a special protein, crystallin. It is held in the organ of vision by special ligaments that help it change its curvature.

The lens refracts light and directs it to the desired areas of the eye. The refractive power of a natural lens is 20-22 D. By changing its shape, a person can distinguish between near and distant objects.

Heterochromia of human eyes: how to treat?

Let us say right away that if this anomaly is congenital, then it cannot be treated or corrected. With the help of surgery, you can only get rid of this defect acquired due to any reason. In all other cases, there is a high probability that your iris color will be restored, but this, again, depends on the reason. With the above-mentioned metallic heterochromia, it will no longer be possible to correct it. Despite this, many people consider this feature even piquant and are proud of being different from the rest. Central or sector heterochromia looks especially unusual and interesting.

Many celebrities are also not shy about heterochromia. For example, Mila Kunis, Mila Jovovich, Demi Moore and other famous Hollywood stars have eyes of different colors and believe that this unusual fact to some extent even contributed to their popularity, attracting attention. For filming, they use contact vision correction, and the rest of the time they feel great.

Advantages and effectiveness of laser iridectomy

Statistical data prove that laser iridectomy is one of the safest techniques for reducing intraocular pressure. The number of successful operations is more than 95%.

Ophthalmologists note many advantages of the procedure:

  • During the intervention, the surrounding tissues are not affected, since the beam acts in a targeted manner;
  • the patient ends up at home in a few hours, he does not need to spend time in the hospital;
  • it is possible to restore the full functioning of the eyeball if the disease is not too advanced;
  • the effect of the procedure is noticeable almost immediately after its completion;
  • low cost and accessibility for most patients;
  • rehabilitation does not take much time (7-10 days).

Contact lenses for heterochromia correction

The simplest and safest method to correct this violation is to use modern decorative optics. Manufacturers of ophthalmic products offer a huge range of contact tint and colored lenses that can be used to hide this defect. Some people with complete heterochromia (for example, one eye is blue and the other is brown) buy models of the colors they are looking for and change the iris the way they want it. If a person is nearsighted or farsighted, he can purchase lenses with the appropriate diopters. If you have good vision, you can simply select the 0.00 option with zero optical power.

So, heterochromia - a congenital disorder of pigmentation of the iris - does not threaten any health consequences if it is not the result of any internal diseases or mechanical damage. People with this disease themselves have different attitudes towards it. Some people consider this a piquant feature and do not hide it; others wear decorative lenses to hide different eyes. But congenital heterochromia of the iris shell can be called rather a rare, unique gift of nature. Many people born with it are gifted, creative individuals, and the above example proves this.

Interesting facts about heterochromacy

In dogs, heterochromacy is most common in the Husky breed.

People are less likely to have different eyes, but, for example, David Bowie had one brown eye and the other blue.

People with heterochromic eyes often have vision problems.

The most beautiful cat in the world in 2021 was proclaimed the Turkish kitten Alosha - a snow-white baby with bright green and blue eyes with a slight braid. The pet is absolutely healthy and hears perfectly in both ears.

In the city of Van (Turkey), a monument to a heterochromic cat was erected, whose blue eye represents the sky and whose golden eye represents the sun.

There is a biblical legend about the odd-eyed Turkish Van. The cat caught a mouse that was destroying supplies on the ark, and Noah stroked his head in gratitude, which is why representatives of this breed have gold spots between their ears.

According to surviving myths, the favorite cat of the Prophet Muhammad, named Muizza, also had multi-colored eyes.

Mystical signs

Psychics agree that animals with different eyes are a talisman and bring good luck. Esotericists believe that such cats have pure energy and can act as family guardians and healers. In addition, it is believed that friendly relations are often established between the odd-eyed cat and the brownie.

If a cat gets in the way and doesn’t let you pass, then good luck awaits the owner.

Superstitions associated with odd-eyed cats:

  • when a cat gets in the way and doesn’t allow you to pass, it means that the owner will soon be very lucky;
  • if an animal disappears from home for several days and returns safely, the cat should be thanked, since its departure most likely diverted impending misfortune from its owners;
  • if an odd-eyed cat crossed the road, then it is better to postpone your immediate plans to another day.

For your information! An interesting fact is that in the Middle Ages, when representatives of the cat family were considered accomplices of dark forces, cats with different eyes were treated much more loyally. Animals whose eyes were painted in different colors were perceived as nothing less than messengers of heaven.

No matter what people and signs say, in any case, an odd-eyed kitten in the house is a great joy for the owners. This wonderful animal will bring harmony to family relationships, and, most importantly, it can become a devoted pet and best friend.

Content Features

In fact, caring for cats with heterochromia is practically no different from caring for animals without such defects. There are no exceptional measures regarding keeping pets as such. Once a day, cats should wipe their eyes. For this procedure, a cotton pad or sterile soft cloth soaked in boiled warm water is best suited. If your pet begins to discharge colored mucus from its eyes, you should consult a veterinarian about this.

As already noted, cats with different colored eyes often suffer from deafness. This ailment requires the owner to have a special approach to the animal. At the same time, competent care can provide a quite decent quality of life for a fluffy.

It is important to diagnose the disease as early as possible. For safety reasons, it is not recommended to let your pet out of the apartment. However, in country houses, if there are barriers, pets can sometimes be allowed for a walk in the yard. If hearing loss occurs suddenly, the cat will need some time to adapt to its new life. During this period, the cat needs increased attention.

If your pet is deaf, it is possible to walk around the yard under the supervision of the owner.

The main condition is to take care of the pet’s safety. It is necessary to carefully inspect all rooms into which the cat may enter for potential dangers. Deaf animals are more likely than others to be listed as missing. Therefore, the cat needs to be microchipped or buy him a smart collar that will allow him to indicate the address and contact information of the owner. If you have other pets (such as dogs), additional preparation will be required.

Important! The owner needs to build communication with the pet. Some experts recommend using gestures or signs to communicate with deaf cats, to which the animals are particularly sensitive. However, it is worth noting that the owner will need quite a lot of time to train.

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