Skip to Content

Why Do Cats Eyes Glow? What’s The Evolutionary Reason For It?

Why Do Cats Eyes Glow? What’s The Evolutionary Reason For It?

You probably have seen a cat’s eyes glow at night and wondered why it happens. We can see it while driving if the cat looks at your beam light. Some people believe this glow is not natural, and it means the cat could be a demon or possessed. But, there’s a scientific reason for this glow.

Cat’s eyes glow because of a group of cells that reflect light. These cells form a tissue called tapetum lucidum that helps improve a cat’s night vision, resulting in better night-hunting. Humans perceive it as a glow, but it is a reflection of visible light. This reflection is known as “eyeshine.”

In this article, we will see more details about cats’ eyes and how they work. In addition, we will learn not all cats glow the same color, and in our FAQ section, you can find some additional answers to the matter.

Understanding The Anatomy Of Cat Eyes

Cat’s eyes are somehow similar to human eyes. Our eyeballs share a cornea to protect the eye and help with light—the sclera, the white part of the eye. In addition, we both share a conjunctiva layer that covers most of the eyeball.

Understanding The Components Of Cat Eyeballs

But there are some differences in cats’ eyes. Let’s talk about the iris; this part of the eye helps regulate light received by the pupils, but cats can voluntarily adjust their pupils’ size. If the cat feels there’s too much light in the environment, it will make its pupils thin to reduce the amount of light received.

Understanding A Cat’s Retina

Another tissue we humans share with cats is the retina. Cat’s retina is much more specialized than the human retina when it comes to light. A cat can see an object with a sixth of the light humans need.

Understanding The Tapetum Lucidum

The retina and the tapetum lucidum are related. Tapetum lucidum is what makes cats so good at moving through the dark. So it is no coincidence cats come equipped with this fantastic feature.

Cats are hunters. Their primary diet is meat-based protein. In comparison, domesticated cats don’t need to hunt for food; wild cats do. Because of their poor vision, these cats prefer to hunt in low light.

To catch their prey, cats use more than one sense. And their retinas come in handy for this purpose. It is essential to know that tapetum lucidum increases the night vision of a cat. But this tissue also reduces the level of definition of the object. Meaning cats can see the object moving, but they can’t identify it by just looking at it.

Tapetum lucidum also helps cats perceive light that is invisible to the human eye. For example, cats can see ultraviolet and infrared rays.

Why Do Cat’s Eyes Glow Different Colors?


There are several reasons why cat eyes glow green, blue, yellow, and even red. The color will depend on the cats’ iris color, age, breed, and health condition.

People claim the color of this glow will vary depending on the cat’s age. They base their theory on personal experience. Scientific research shows that as the cat ages, its ability to see in the dark decreases.

Others believe the breed is a factor. People widely think that Siamese cats have a yellow glow. But most domestic cats reflect a lime-green color.

Several people on the internet also believe blue-eyed cats will have a red reflection, just like humans.

And some experts claim the color changes because of the number of vitamins and minerals in your cat’s body. High amounts of vitamin B2 will increase the yellow color. In contrast, high levels of zinc will cause a blue color.

What Does It Mean When A Cat’s Eyes Glow Green?

It means that your cat’s eyes are reflecting the light directly to the source. The tapetum lucidum causes this effect.

Frequently Asked Questions

When Do Cat’s Eyes Glow?

Cat eyes will only glow when under low-light conditions if a light is beamed directly into their pupils.

Is Tapetum Lucidum A Protective Tissue?

No, it can’t be considered a protective tissue. Instead, its primary function is to help night vision.

What Color Is The Tapetum Lucidum?

Several sources claim this tissue has a color. Experts say the tissue color is iridescent—something like the colors you see in soap bubbles.

Do Humans Have Tapetum Lucidum?

No, humans don’t have this layer in their eyes. People claim that’s the reason why camera flashes cause a red-eye effect on pictures.

My Cat’s Eyes Don’t Glow In The Dark, Should I Worry About It?

We suggest it’s better if you take your cat to a vet and have it checked. Typically cats have this natural ability, and people claim old cats can lose it. Make sure you don’t try to beam random light at your cat’s eyes at home because you can damage its vision.

Can Lights Harm My Cat’s Eyes?

Cats are very good at identifying threats. They won’t stare at a source of light unless it is necessary. However, there might be cases where cat owners or members expose your cat to light. Let’s talk about some of the most common and what they do to cat’s eyes.

LED Lights

LED lights won’t cause any damage to your cat’s eyes. But make sure the lights don’t blink, as they can negatively affect your cat’s vision. Overall, LED lights are a good option.

Light Bulbs

Light bulbs can irritate your cat. Make sure you don’t expose your pet to lights. Prolonged exposure can lead to issues with your cat’s vision.

Invisible Lights

These include infrared lights (IR) and ultraviolet lights (UV). Both of these lights are invisible to the human eye. But cats can see them. Some laser tags use this type of light, and you should be careful when playing with your cat. As we mentioned, extended exposure to any light can damage your cat’s vision.

Do Other Animals’ Eyes Glow?

Yes, other animals come equipped with tapetum lucidum tissue. Some examples include:

  1. Cows
  2. Calves
  3. Fish
  4. Dogs
  5. Spiders
  6. Raccoons
  7. Lemurs

Are Cats Born With “Eyeshine” Or Do They Develop It?

Cats are born with the tapetum lucidum layer. These are part of the natural features that prepare them for low-light environments.

Diseases That Can Affect Night Vision In Cats


Now you understand what happens in a cat’s eyes when they glow at night. Your pet uses night vision to walk around your home without stumbling into your furniture. However, there are degenerative diseases that can reduce your cat’s night vision:

  1. Progressive Retinal Atrophy, also known as RPA, is a disease that can affect cats. It makes their eyeshine less bright, and your cat can feel uncomfortable under low-light conditions. This condition could leave your cat utterly blind in a matter of years.
  2. Feline central retinal degeneration (FCRD) is a disease caused by a low level of taurine. Taurine is an essential protein, and cats receive it through food. Most commercial cat foods provide the correct levels of protein to cats. However, the deficiency usually happens when you subject your cat to a homemade diet. Therefore, it is essential to talk to your local vet about your pet’s needs before deciding on a diet.

How Can I Protect My Cat’s Tapetum Lucidum

There’s not a specific technique to help your cat protect its eyeshine. But there’s no need for you to worry much about it because this is the third layer of a cat’s eye.

You can take care of your cat’s eyes by externally wiping them with a cotton swab. Make sure you don’t apply any chemical products to the eyeball. You could cause damage to your cat’s vision.

Other Uses Of “Cat Eyes”


In road marking, “cat eyes” are the name of marking devices installed on the pavement. These devices reflect the light directly back to the source. You can usually find them placed along lane lines.

We can agree this term comes from the ability a cat’s eyes have to reflect light.

Final Thoughts About Cat’s Eyes

Now we understand cats’ eyes are similar to human eyes, but not quite the same. The eyeballs in humans and cats are similar, but cats have specialized night vision. As a result, they can see much more objects under low light conditions than we humans can.

The glow we see is just a component of their night-vision structure. It helps cats capture more light from the environment. But at the cost of reducing the accuracy of their vision.

Depending on their breed, age, and health condition, cats’ eyes can glow in different colors. The most common are green and yellow. But you can find cats with a red glow.

Cat’s eyes are susceptible to light. The good thing is they are capable of regulating their vision. And that there’s nothing wrong with this glow.