Cats’ eyes are one of their most distinctive features. They are very different from the eyes of other animals because they range widely in color and have a unique pupil shape.

The science behind cat eye colors is fascinating – there are a number of different genetic factors that determine a cat’s eye color.

Here are some fascinating facts you may not have known about cat eye colors.

The Fascinating Science Behind Eye Color

cat eye colors

Cats’ eye colors are determined by the amount of melanin they have in their eyes. Melanin is a specific type of amino acid that produces color in the eyes as well as in the rest of the body.

Cats have different melanin levels in their fur and their eyes, which is why cats with light fur can have dark eyes and vice versa.

Cats have cells called melanocytes in their eyes, which release the melanin pigment. When these cells are more active, they release more melanin, which results in deeper colors.

The melanocytes are located in the iris. The iris is the circular colored section of the eye around the pupil.

The activity level of the melanocytes is determined by genetics. If a cat’s mother had deep amber eyes as a result of active melanocytes, it’s very likely that her kittens will too.

Because of this, purebred cats often have more intense eye colors. Purebred cats’ genetics are much more carefully controlled than other types of cats, which is why their eye colors are likely to be deeper and brighter.

Why are my kitten’s eyes changing color?

kitten eye colors

If you’ve raised a kitten, you’ve probably noticed that their eyes change colors as they get older.

Kittens are born with their eyes closed, and their eyes don’t start to open until about one week after birth. Their melanocyte cells aren’t active at this point, so when their eyes do open, they will be a very pale blue shade.

Over the next several months, the melanocyte cells become active and the cat’s permanent eye color will develop.

You’ll see the cat’s adult eye color start to come in after about six weeks.

Their melanocyte cells will continue to release pigment, and most cats’ eyes are fully developed at around the age of four months.

What happens if a cat’s eyes change color as an adult?

While it’s normal for kittens’ eyes to change color as they are developing, a change in eye color as an adult could be an indication of health problems in a cat.

Specifically, if your cat’s eyes become orange when they were previously a different color, it could be an indication of a condition called uveitis.

There are a number of serious underlying health conditions that lead to uveitis. When this happens, it could be an indication of diabetes or high blood pressure, or a viral, bacterial, or fungal infection.

There are other eye conditions that can cause the iris to become cloudy or milky white, specifically glaucoma or cataracts. High blood pressure can cause the pupil to become large and sometimes pinkish in color. Lastly, bleeding into the eye can cause a change of iris colour to red- it often occurs as a result of trauma or blood pressure problems.

If you notice that your cat’s eyes have changed color as an adult, take them to the vet to make sure that any underlying conditions are appropriately treated. Many of these conditions will cause blindness if not corrected quickly.

Heterochromia – Cats With Different Colored Eyes

cat with different eye colors

You may have seen striking photos of cats with two different colored eyes. This is called heterochromia. This happens when a genetic mutation blocks melanocyte activity in one eye.

Typically, cats with this condition have one eye that is blue and another eye that is either green, yellow, or orange. This is most commonly found in white cats, but can be found in other types of cats as well.

There are also cats with dichromatic eyes, which have two different colors in the same eye. This condition is very rare and very striking. Cats with dichromatic eyes can either have two differently colored rings, or can have the color split down the middle.

Inside Cat Eye Colors

Cats have a very broad spectrum of possible eye colors. Some of the most common eye colors for cats include:

Blue eyes

Cats with blue eyes have the least melanin. It is very common for white cats to have blue eyes, and albino cats always have blue eyes. Some grey cats also have blue eyes. Statistically, white cats with blue eyes have a much higher chance of being deaf than cats with other eye and fur color combinations.

cat blue eye colors

Albino cats are different from white cats in that they have absolutely no melanin in their body. Because of this, their eyes are going to be extremely light and almost reflective. Their eyes are very sensitive and are more susceptible to sun damage.

Green eyes

green cat color eyes

Green eyes also have very little melanin in them. However, they contain more melanin than blue eyes. It is very common for cats of many different fur colors to have green eyes, and they are often very striking.

Yellow/orange eyes

yellow cat eye color

Cats with yellow or orange eyes have much more melanin than cats with blue or green eyes. It’s very common for black or brown cats to have these darker eye colors, but cats of any color can have them. Many feral and wild cats have these darker eye shades as well.

Cats’ eyes are very bright and hypnotic. There are so many different eye and fur combinations possible for cats, so each one is completely unique. The melanocytes in each cat’s eyes determine their bold individual eye colors. It’s normal for eyes to change color in young kittens, but after 4-6 months of age the eye color should be set- meaning if you notice a change you should seek a vet’s advice.