In my youth, the more I see a cat in the dark I see a glow in her eyes and I thought it contained radium (radioactive material) causing this glare, but the real reason for the glow of these eyes was not radium!

What causes this glow?

"The eyes of some animals (cats, dogs, horses, etc.) are characterized by the presence of a special reflective layer in the back of the eyeball. The task of this layer is to absorb the light more effectively and more efficiently by the light receptors in the eye."

What is the Tapetum Lucidum?

This layer is located in the back and end of the retina in vertebrates (cats, dogs, horses, etc.) and increases the amount of light available for absorption by the optical receptors in the eye, You may wonder what these photovoltaic receptors are?

Well, it's a particular neurotransmitter that turns light into neurotransmitters that move to the brain to see vision according to another biological strategy we're not going to mention now.

Have you ever heard of sticks and cones in the eye?

We believe that you have heard of it in one of your classes. The function of these cells is to help distinguish different colors and help us see the night too. But what you do not know is that sticks and cones are just two kinds of optical receptors. Of these receptors are found in mammalian nets.

The answer is simple. This layer absorbs the light directed towards the eye and reverses it toward the optical receptors, which brings together the original light and the reflected light. This gives the photoreceptors a second chance to absorb the light better, producing a clearer image at night. Tonight, the negative effect is that animals that can see at night do not see things clearly and clearly, but see it hazy as a result of reflection and absorption of light, and resulting in dazzling and blurred.

We do not see the eyes of all animals glow the same color in the dark, although this layer is a layer of a special color, due to the difference in the visible color of the metal elements that consist of this layer and on the corner that we see the eye, the most bright colors of the eyes of animals we see In nature are: white with blue edges in dogs, green color in the tigers, golden green color with blue edges in the deer

Many animals, especially the night, have this layer and this glow, and this helps them to see better at night, giving them a natural preference during hunting at night, or while escaping from the enemies at night too, and note that some aquatic animals also have this layer as karks and crocodiles.

Humans can see the glow of animals' eyes at night, distinguish between different brightness colors, and use dogs and horses trained in night searches because they see better than humans in the dark. Humans also made a layer similar to this layer, The roads so drivers can see them in the dark.

You can label these signs with night cat eyes.

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Sources

scienceabc