Raised Pavement Markers – Have you ever turned a darkened room and been met with bright eyes looking directly at you? The luminous eyes in the dark can be startling and even frightening if they appear unexpectedly. According to ancient Egyptians, cats were thought to catch the shine of the sunsets in their eyes and make it secure until dawn. The ancient Greeks assumed that there was a shining fire-like source of illumination within the eyes. We also understand that cat eyes seem to shine like the eyes of several other nighttime creatures since they emit illumination. 


Although all eyes emit illumination, some have a particular reflecting form called a tapetum lucidum that gives them a dazzling look at nighttime. It essentially allows these creatures to see exceptionally effectively in the dark. It’s also what generates “eyeshine,” the characteristic of a bright eye.


What is the process? 

When light penetrates a cat’s eye, it can go in one of several directions. Some light reaches the retina, a region behind the eyeball that contains light-sensitive receptors. These sensory receptors provide nerve signals via the optic nerve, translated into a mental picture. 


The tapetum lucidum receives some of the illuminations that go via or across the retina. The tapetum lucidum bounces visible radiation back through the retina, allowing photoreceptors to receive more light. It enables cats to see in the darkness easier than people.


What do the various colors of glowing eyes imply? 

The illumination we perceive from a cat’s eye can be various colors, but the most common are azure, emerald, and golden. Cats’ eyes are made up of chemicals like riboflavin and zinc, and the amount of zinc in them influences the color of their eyes. Kittens are created with blue eyes, just like infant babies made with blue eyes that deepen with time. As a result, kittens will always have bright blue eyes; however, the color will gradually switch as they mature. 


Because the tapetum lucidum becomes least effective with age, kittens’ eyes are prone to shine clearer than mature cats. It can make their eyes look darker as they get older, but it’s nothing to be concerned about. 


Note: If your cat’s eyes are reddish, specifically at night, it could be a sign that illumination is no more accessing the tapetum lucidum, which is more prevalent in elderly cats.


What if my cat’s eyes shine brightly throughout the day? 

In simpler terms, your cat’s eyes must not sparkle during the day. The radiance indicates pupils have widened and are permitting excessive illumination into their eyes, which should not be the case in the daytime. It might mean a concern with their eye(s); thus, it’s critical to have them evaluated by a veterinarian if this happens. 


When your cat is in a darkened environment, its eyes must always seem reflecting. If your cat’s eyes don’t shine in soft lighting, they’re probably suffering from eyesight problems. It might be glaucoma, cataracts, or conjunctivitis, and they must contact a veterinarian.



This article has given you simple explanations on why cats’ eyes glow. From this explanation, you can also draw a reference to why the concept of “cat eyes” in the road engineering field also glows, especially at night. 


Cat eye in the road construction industry refers to the double lines, often yellow in color, that is drawn in the middle of roads to signify demarcations. These lines often shine respectively at night so that can be visible and easily identified.