You may have wondered whether cats see the world in color, as humans do, or do they see in black and white? The answer to understanding cat vision lies in the science of the feline eye!

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The eyeball is shaped like a ball. It consists of an outer “shell” that creates the spherical shape, and inner contents of a lens and fluid. The lens is a structure that focuses the incoming light and directs it through the back of the eye and on to a specialized, thin layer of cells, known as the retina. The cells in the retina are named after their shape, rod cells and cone cells. Rod cells are effective in dark/dim light situations and are excellent at detecting motion. Dogs and cats have large numbers of these cells in their retina, so they have much better vision at night-time than us. Cone cells function in bright light and allow color vision. There are different types of cone cells, with some detecting red light, some detecting yellow/green light and some detecting blue light. Human eyes possess all three types of cone cell and so we can detect a rainbow of color vision. Cat’s eyes possess only two types of cone cells (blue and yellow/green) and so cats do see colors in the blue and yellow spectrum, but do not see red colors. They also see black and white and shades of gray. This type of two-shade colour vision in cats is called “dichromatic vision”. “di” means two and “chromatic” means color, so, two-color vision.

Yes! In fact, our cats have many more rod cells in their retina than we do. Rod cells are highly sensitive in low light conditions. The pupil of the eye can get bigger and smaller, either to protect the eye from bright light (gets smaller), or to enlarge and let more light into the eye in dim light. A large pupil allows more light into the eye in dim light conditions. Cats also have a reflective structure in their retina, called the tapetum lucidum. This enhances vision in the dark. We often see it reflecting when a light shines in their eyes.

Color blindness, or color vision deficiency, affects some people (more often men) and occurs when certain types of cone cell are missing from the retina, or are present but are not working properly. In humans, any of the three types of cone cell can be missing. For example, if the red cone cells are missing, then the person will not see shades of red and so these people may see the world in a similar way that cats do. Affected people often struggle to differentiate between colors, so that red and green may appear the same to them, or blue and yellow may appear the same. For this reason, their type of color blindness may be called “red-green color blindness” or “blue-yellow color blindness”.

Visual acuity is what we call the ability to see detail. Humans have a superior ability to see in detail, about 2.5 times the ability of dogs, and about 10 times the ability of cats. It is also common for cats to experience what's known as "refractive error", making them long-sighted or short-sighted. However, little is known about what degree of refractive error can be present. These changes rarely cause any difficulty as cats will rely on their superior senses of hearing and smell to compensate for the reduced vision. Because cat eyes are positioned further apart than human eyes, cats also have a wider field of view than humans do (known as peripheral vision). This means that they can see a wider area than we can. Dogs have an even wider field of vision than cats, as their eyes are set further apart. Cats are not as good at judging depth perception as humans, our close-set eyes (binocular vision) make humans better at this. Cats are unable to focus on objects closer than 25cm from their eyes, so rely on their sense of smell for closer objects.

So, cats see shades of blue, yellow/green, grays, black and white, but they can’t see shades of red. They make up for this reduced color vision with good night vision and better peripheral vision than humans. Cats have highly developed other senses such as hearing and smell which also help them understand and thrive in the world around them. Just like us, cats can develop problems with their vision. If you notice your cat has a sudden change in behavior such as reluctance to jump or climb, or any disorientation and are worried that their sight may be affected, then always make your veterinarian your first port of call. There are many excellent treatments available to help cats with eye problems and it is always best to start treatment sooner rather than later.