6 Vet-Verified Facts About Cat Eye Colors: Vision, Kittens & Coat Impact
Your cat's eyes are the windows to their soul, so it's no wonder they're so pretty, but a lot is going on behind those sparkly blues, autumn golds, or emerald greens. When you get into the nitty-gritty, there are some seriously fascinating facts to discover about the inner workings of a cat's eyes and how their color is determined, so let's gaze a little more deeply into this.
Top 6 Facts About Cat Eye Colors
1. Kittens Are Born With Blue Eyes
Though some breeds, like the Siamese and Birman, are known for their stunning sapphire-blue eyes, every cat is blue-eyed at the very beginning. This happens because it takes around 6 to 7 weeks for the iris (the colored part of the eye) to start producing the melanin responsible for its pigmentation.
Melanin comes from cells called melanocytes, and these are contained within the layers of the iris called the stroma and the epithelium.
2. Melanin Determines Eye Color
A cat's eye color depends on the amount and type of melanin produced by their melanocytes (the melanin-producing cells). Cats with more melanin have darker eyes, whereas cats that have minimal amounts of melanin have blue eyes.
Blue-eyed breeds include the Siamese, Birman, Himalayan, Ragdoll, and Persian, to name a few. Green-eyed cats have some melanin, but not as much as orange/copper-eyed cats.
The type of melanin also plays a role in cat eye colors; eyes with more eumelanin are brown, eyes with more pheomelanin are yellow, and eyes with lower levels of pheomelanin and eumelanin are blue or green.
3. Cats Don't Have Dark Eyes
The darkest possible shade cat eyes can have is copper, which is more of an orange-brown than full brown, like some dogs have. While cats can have black and brown coats and markings, they can't have truly brown or black eyes.
4. Refraction Makes Eyes Appear Blue
Blue eyes in cats are not caused by blue pigment. Instead, they appear blue due to light scattering in the stroma of the iris, a phenomenon known as the Tyndall effect. The iris contains very little melanin in blue-eyed cats, so incoming light is scattered and refracted, reflecting shorter (blue) wavelengths back to the observer. Without this light scattering, the iris would appear colorless or very pale.
5. Fur Color and Eye Color Aren't Strongly Linked
While it's true that certain breeds, like the Siamese, are typically blue-eyed, other eye colors aren't linked to specific coat colors or types. Blue-eyed breeds receive the dominant white coat gene, which overrides any possibility of the cat developing other eye colors like amber, copper, golden, green, or hazel. Unfortunately, the same gene is linked to a stronger incidence of deafness.
6. Heterochromia Causes Different Colored Eyes
Cats with odd-colored eyes—such as one blue eye and one amber eye—have a condition called heterochromia. This occurs when melanin is unevenly distributed in the irises during development, resulting in one eye with normal pigmentation and one with very little or no melanin. The blue eye appears blue due to light scattering rather than pigment.
Some cats have sectoral heterochromia, where a single iris contains two colors, for example, part yellow and part blue.
Heterochromia does not affect a cat’s vision. White cats with blue or odd-colored eyes are at higher risk of congenital deafness, but odd-eyed cats that are not white do not have an increased risk of hearing problems.
What's the Rarest Cat Eye Color?
Copper—the darkest color a cat's eyes can be—seems to be the rarest single color. Copper is a reddish-brown shade, possibly with an orange tone. On the other hand, yellow, amber, green, and hazel-colored eyes are much more common.
While copper is one of the rarer single colors, it's even rarer for cats to have heterochromia (odd-colored eyes). Dichromatic eyes (irises with more than one color as described above) are especially rare.
Conclusion
While eye colors in cats can vary greatly, no matter what color eyes your cat has, they're all beautiful! That said, if you notice anything new or unusual about your cat's eyes, like dark spots or redness, please consult a vet, as it could be a sign of a medical issue that requires attention.
See Also:
Featured Image Credit: Firn, Shutterstock
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Kit Copson is a freelance writer and lifelong animal lover with a strong interest in animal welfare. She has parented various furry beings over the years and is currently a proud cat mom of two—one very chilled (unless hungry) Siamese and a skittish but adorable Domestic Shorthair—and dog mom of one—an adopted Bichon Poodle cross. When not writing about or spending time with animals, Kit can be found doodling in her sketchpad, reading, or more often than not, drinking tea.
