The Eyesight of a Cat: Anatomy, Color Vision & How Cats See Us

Written by: Rachel Holly

Ever wonder what your cat really sees when they look at you? Do they see the world as we do? More color? Less color?

Cats possess a highly specialized set of sensory abilities, and their eyesight plays a key role in how they interact with their surroundings. Their sight is fine-tuned to help them navigate their world as skilled hunters and nocturnal creatures. While their vision may not be as sharp as that of humans, it is perfectly adapted for their ancestral needs as hunters and nocturnal predators. Today, we look at the anatomy of a cat’s eye, their color vision, and how they really see our world.

The Anatomy of a Cat’s Eye

A cat’s eye is anatomically similar to ours, however, the differences that do exist create greater ability in low-light environments and for focusing on quick, subtle movements. The main parts of the cat’s eye include the cornea, lens, retina, pupil, and the tapetum lucidum, each playing a critical role in vision.

• Cornea and Lens: Like humans, cats have a cornea and lens that work together to focus light entering the eye onto the retina. However, cats have a wider cornea and a more powerful lens that we do, which allows for better focus in dim lighting and for detecting movement. Together, the cornea and lens provide the necessary adjustments for the cat to see clearly in various lighting conditions

• Pupil: A cat’s pupil is elliptical-shaped, which will contract to a very narrow slit in bright light and dilate into a wide oval in low-light conditions. This ability to adjust rapidly helps cats maintain sharp vision in varying levels of brightness. A cat’s pupil can expand up to 50 times the size of a human’s pupil in the dark, allowing more light to enter the eye in the dark.

• Retina: The retina at the back of the cat’s eye contains millions of photoreceptor cells, including rods and cones.It is the light-sensitive layer at the back of the eye. Rods are responsible for vision in dim light, and cats have a higher density of rods compared to humans; thus greater night vision. Cones, which are responsible for color vision and visual detail, are fewer in cats than in humans, and this lessens the cat’s ability to see details and vibrant colors.

• Tapetum Lucidum: Cats also have a special reflective layer, which humans lack, behind the retina called the tapetum lucidum. This structure acts like a mirror, reflecting light that passes through the retina back into the eye, giving the photoreceptors a second chance to capture it. This enhances their night vision, making it much better than that of humans and most other animals. The tapetum lucidum causes the cat’s eyes to glow when light hits their eyes at night.

• . Sclera, Iris, and Other Components
• The sclera, the white part of the eye, is the outer protective layer that maintains the shape of the eyeball. While it is rather obviously in humans, it is typically less visible in cats due to the shape of their eyes and their fur. The iris is the colored part of the eye, which surrounds the pupil and controls its size. It adjusts in response to light and helps with focusing, working together with the pupil to regulate how much light enters the eye.

Color Vision: How Cats See Color

Unlike humans, who have three types of cones in their eyes that allow them to see a broad range of colors, cats have only two types of cones. This means less ability to see color and, though they can distinguish between some colors, their color vision is not good as that of humans and other animals.

• Dichromatic Vision: Cats are considered to be dichromats, meaning they can perceive only two primary colors. While humans can see a spectrum of colors ranging from reds to blues and greens, cats primarily see shades of blue and green. They have difficulty distinguishing between red, purple and pink, which may appear as shades of gray or a brownish color to them.
• Shades of Blue and Green: Cats can see blues and greens with relative clarity. This reduced color perception, however, does not affect their success as hunters. Their vision is optimized for detecting movement, not identifying various colors.

How Cats See the World

To understand how cats see, it’s important to consider their evolutionary past. Cats are crepuscular, meaning they are most active at dawn and dusk, and their vision is adapted for hunting in during these times. So while human eyes are designed to see fine detail and color, the cat’s eyes are specialized for spotting movement in the dark.

• Night Vision: Thanks to their high rod-to-cone ratio and the tapetum lucidum, cats are excellent at seeing in the dark. Their vision in the dark is six to eight times better than that of humans. However, it’s worth noting that cats’ vision in the total darkness is limited—without any light at all, they cannot see well, just like us.
• Field of View: Cats have a wider field of view than humans, with approximately 200 degrees compared to a human’s 180 degrees. This allows them to be highly aware of their surroundings, taking in a broader view, especially when they’re hunting. Their peripheral vision also helps them detect the slightest movement, which is crucial for both hunting and defense.
• Depth Perception: While cats’ eyes are positioned more to the side of their head, giving them a broader field of view, their depth perception is less accurate than ours. To detect the distance of objects or prey, the cat will rely more on their other senses, such as smell and hearing.

Here’s a great visual comparison of who cats and humans see the same thing differently: https://www.livescience.com/40460-images-cat-versus-human-vision.html

A cat’s eyesight is finely tuned to meet the needs of its past predatory lifestyle is an fascinating example of evolutionary adaptation. While they may not perceive the richness of colors that humans do, their vision excels in low light and is keenly attuned to movement, making them skillful hunters. With unique anatomical features like the tapetum lucidum and a high ratio of rod cells in their retinas, cats are built to thrive in environments with limited light. Understanding the nuances of their eyesight highlights just how well-adapted cats are to their role as nocturnal predators in the wild and gives us a clue as to what our felines see when they look out at the world.