When Do Cat's Eyes Change Color? Your Cat Eye Guide

cat eyes: a guide to when they change color and why

Cat eyes are known for their stunning appearance, and the ability to change color is one of their most distinctive traits. A cat's eyes can appear to change color due to a variety of reasons, including age, health, genetics, and lighting conditions. This article will explore the science behind cat eyes changing color and when it occurs.

The Anatomy of Cat's Eye

Anatomy of a cat's eye

To understand how and why cat eyes change color, it's important to first understand the anatomy of a cat's eye. A cat's eye is composed of three layers: the outermost layer, the cornea, is a clear, protective layer that covers the eye's surface. The middle layer, the iris, is the colored part of the eye and contains muscles that contract or expand to adjust the size of the pupil. The pupil is the black center of the eye that regulates the amount of light entering the eye. The innermost layer, the retina, contains cells that respond to light and send signals to the brain, allowing the cat to see.

Why Do Cat Eyes Change Color

The color of a cat's eye is determined by the amount and distribution of pigments in the iris. Melanin is the pigment that gives color to the skin, hair, and eyes. The more melanin in the iris, the darker the eye color. A lack of melanin results in lighter eye colors, such as blue, green, and yellow.

One reason why cat eyes can appear to change color is due to the dilation and contraction of the pupil. In bright light, the pupil constricts, causing more pigments to be concentrated in a smaller area, making the eyes appear darker. Conversely, in dim light, the pupil dilates, causing the pigments to spread out over a larger area, making the eyes appear lighter.

Another reason why cat eyes can change color is due to the amount of light reflecting off the iris. The iris has a layer of reflective cells, called the tapetum lucidum, which reflects light back through the retina, increasing the cat's ability to see in low light conditions. The tapetum lucidum is also responsible for the glowing effect in a cat's eyes when light is shone on them in the dark. The color of the tapetum lucidum can range from gold to green to blue, and can contribute to changes in eye color.

When Do Cat Eyes Change Color?

Now that we understand the anatomy of a cat's eye, let's explore when cat eyes change color. There are several factors that influence when a change in color might occur, including:


As cats age, their eyes may change color. This is because the lens of the eye becomes less flexible over time, causing the eye to appear more yellow or cloudy.

A cat's eye color is usually determined by genetics and remains the same throughout their life. However, there are some instances where a cat's eye color can change due to age. In kittens, eye color can change as the melanin levels in the iris increase. Kittens are often born with blue eyes due to the absence of melanin in the iris. As the kitten grows and develops, melanin is produced, causing the eye color to change. Most kittens' eye color changes by the time they are three months old, but it can take up to six months for the eye color to fully develop.

In older cats, eye color changes can occur due to health issues such as cataracts, glaucoma, and uveitis. Cataracts occur when the lens of the eye becomes cloudy, causing vision loss and a change in eye color. Glaucoma occurs when there is an increase in pressure in the eye, damaging the optic nerve and causing a change in eye color. Uveitis is an inflammation of the iris, which can cause the eye color to appear lighter or darker.


A cat's eye color can also be an indicator of their health. Cat's eye color may change if a health issue is present, such as an infection or injury. For example, if a cat has an eye infection, their eyes may appear more red or swollen than usual.

Yellow or orange eyes are common in cats and are a result of the high levels of melanin in the iris. However, if the whites of the eyes appear yellow, it can be a sign of liver disease.


Some cat breeds, such as Siamese and Burmese cats, are known for their color-changing eyes. These cats have a gene that causes their eyes to change color based on the temperature of their environment.


The lighting in a room can also cause a cat's eyes to appear to change color. For example, if a cat is sitting in a room with bright sunlight, their eyes may appear more golden or green than usual. Lighting won't change the eye color, but it will give a different appearance.


Final Thoughts

In conclusion, a cat's eye color changes as a result of the amount and type of pigment present in the iris. While most cats' eye color changes occur during their first few months of life, some cats may experience changes later in life due to genetics, illness, aging. If you're concerned about your cat's eye color, it's always best to consult with a veterinarian to determine the cause and appropriate treatment.


Frequently asked Questions

Why Do Cat Eyes Glow?

Glowing cat eyes

Cats have a layer of tissue in the back of their eyes called the tapetum lucidum, which reflects light back through the retina, giving the retina a second chance to detect the light. This layer also causes their eyes to appear to glow or shine when light is shone on them.

When light enters a cat's eye, some of it is absorbed by the retina and some of it passes through to the tapetum lucidum. The tapetum lucidum reflects the light back through the retina, increasing the amount of light available for the retina to detect, and enhancing the cat's night vision. The reflection of the light in the tapetum lucidum causes the cat's eyes to appear to glow or shine in low light conditions, such as when a light is shone directly at them in the dark.

This is also why you may notice that cats' eyes seem to glow more brightly in the dark than in well-lit environments.

Why Do Cat Eyes Dilate?

Cats have a unique ability to control the size of their pupils, which allows them to adjust the amount of light that enters their eyes. The dilation of a cat's pupils is a reflexive response to changes in their environment.

When the light is bright, a cat's pupils will contract, becoming smaller to reduce the amount of light entering the eye. Conversely, in low light conditions, their pupils will dilate or become larger to allow more light to enter the eye and improve their vision.

Additionally, a cat's pupils can dilate in response to emotional and physical stimuli such as excitement, fear, or pain. When a cat is aroused or feels threatened, their pupils will dilate to allow them to take in more visual information and react appropriately to the situation.

In summary, cat's pupils dilate in response to changes in their environment and to emotional and physical stimuli. This allows them to maintain optimal vision and respond to various situations appropriately.

Why Are Cat Eyes Slit?

cat eyes with narrow slits

The slit-like shape of a cat's eyes is actually an adaptation that helps them to hunt effectively. Cats are predators and rely on their vision to track and catch prey. Their slit-shaped pupils are able to adjust quickly to changes in light, allowing them to see better in low-light conditions, such as during dawn or dusk when many of their prey are active.

Additionally, the elongated shape of their pupils helps them to focus more accurately on objects in their visual field. This is because the shape of the pupil allows more light to enter the eye when the cat is looking straight ahead, and less light when the cat is looking to the side. This makes their vision more acute and enables them to judge distances and track movement more accurately, which is particularly useful when hunting prey.

Overall, the slit-like shape of a cat's eyes is an evolutionary adaptation that has helped them to become successful hunters, and it is one of the many unique features that make them such fascinating and beloved pets.

How Do You Clean Cat Eyes?

Cleaning a cat's eyes can be important to maintain good hygiene and prevent infection. Here are the steps to clean your cat's eyes:

    1. Prepare the materials: You will need a clean, soft cloth or cotton ball and a small amount of lukewarm water or saline solution.
    2. Approach your cat: Approach your cat calmly and gently. Talk to your cat in a soothing voice to help them relax.
    3. Wipe away any discharge: Gently wipe away any discharge from the corners of your cat's eyes with the damp cloth or cotton ball.
    4. Clean the eyes: Dip a fresh cotton ball or corner of the cloth into the water or saline solution, then gently wipe the area around your cat's eyes.
    5. Dry the area: Use a dry, soft cloth or towel to gently dry the area around your cat's eyes.
    6. Reward your cat: Reward your cat with treats or playtime to help create positive associations with the cleaning process.

      It's important to note that if your cat's eyes appear red, swollen, or if they have excessive discharge, it's best to seek veterinary care as this could be a sign of an infection or other health issue.

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