Can Cats See in The Dark
Considering that cats are more active at night, we might jump to the conclusion that they have great night vision. While we wouldn’t be completely wrong, it turns out that cats have advantages and disadvantages when it comes to their ability to see in the dark. Another interesting fact is that cats aren’t actually nocturnal—they’re crepuscular, which means that they are more active during the dimmer, changing twilight hours of dawn and dusk. What exactly do we know about cats, their eyes, and night vision? Keep reading to find out more about this fascinating feline topic!
How Cats Eyes Function
Cats’ eyes function in a way that’s similar to our own, but their eyes have certain structural differences that make them see the world differently than we do.
At night, when it’s particularly dark, the cornea, retina, iris, pupil, and lens of your cat’s eyes work together to help them during their hunting expeditions.
In the front of a cat’s eye is the cornea, which serves as the first barrier of protection for the eye. It also allows light into the eye and focuses it onto the retina at the back of the eye. The retina contains cells that detect light called photoreceptors.
The iris, or colorful part of the eye, is responsible for controlling the amount of light entering from the cornea. This is because it controls the expansion and shrinkage of the pupil, which is the black circular at the center of a cat’s eye. In low light settings, the pupil will enlarge to allow more light in, and in brighter light the pupil becomes smaller to reduce the amount of light entering the eye.
The lens can be found behind the iris, and it also has a role in focusing light onto the retina. The lens also contains small ciliary muscles that contract and relax (just like all muscles do). When contracted, the lens thickens and helps cats focus on objects that are closer. When relaxed, the lens becomes thinner, which helps cats focus on objects that are farther away.
How Does Night Vision Differ Between Cats and Humans?
The retina holds the key to one of the biggest differences between cat and human eyesight. There are two main photoreceptor cells in the retina: rod cells and cone cells.
Rod photoreceptor cells are responsible for vision in low light conditions and for detecting and following movement.
Cone photoreceptor cells detect color and adjust for brightness, but do not work as well in low light.
Cats have more rod cells and fewer cone cells than humans. This abundance of rod cells allows them to sense shapes and objects in the dark better than we can, but not necessarily at the same level of detail.
The greater amount of cone cells that humans have means that we can see more vibrant colors during the daytime than cats can, as well as see objects with greater resolution/detail during the day.
With more rod cells, cats can detect and follow movement more easily than humans can in low light conditions. The cone cells in cats’ eyes help them to assess speed and distance. As you can imagine, the functions of both the rod and cone cells in cats’ eyes are very useful for kitties who are on the prowl for rodents and other creatures that may be scurrying around at night!
Range of Vision in Cats Versus Humans
What else do we know about cats' eyesight and how it differs from our own? Cats have better peripheral vision than humans, in addition to an overall wider field of vision (around 200 degrees) in comparison to the typical 180 degree field that humans have. These features give cats the ability to see more of what's around them, both during the day and night.
Are Cats Nearsighted?
While cats can be nearsighted, it's not something that can be attributed to all cats (as is the case for humans). Nearsightedness occurs due to a refractive error where light coming into the eye focuses on the front of the retina (as opposed to behind the retina with farsightedness), resulting in blurry vision.
Nearsightedness is often confused with the function of rod and cone cells in a cat's eye and how this relates to cats seeing objects with lower resolution/detail than humans in many cases during both day and night.
Why Do Cats' Eyes Glow in the Dark?
When we look back at the image above that details the structure of a cat's eye, we can see that near the retina at the back of the eye is something called the tapetum lucidum. This structure catches light that may have passed between the rod and cone photoreceptors and is not absorbed by the retina, and reflects this light back to them to provide another chance for supporting their vision in the dark. Inevitably, some of this light is still not picked up by the photoreceptors and that light escapes and reflects back out from the eye, which accounts for the infamous shine that we see when looking at a cat's eyes in the dark. The tapetum lucidum provides greater light sensitivity, and it is estimated that this structure allows a cat to see six to eight times better than we can in the dark.
Do Some Cat Breeds See Better in the Dark?
Currently, there isn’t strong evidence that some cat breeds see better in the dark than others. However, there is research on eye problems to which some cat breeds are more prone, which could affect a cat’s ability to see in daylight or darkness. For example, progressive retinal atrophy (PRA) is an eye disorder that causes retinal degeneration. There are different forms of this condition—early onset, which is an inherited disorder also known as retinal dysplasia, and late onset PRA. While their timeline of progression differs, these conditions typically affect both rod and cone cell function, leading to progressive vision loss and ultimately blindness. Research shows that the Abyssinian, Persian and Persian-derived breeds, such as the Himalayan, are at a higher risk for the inherited form of PRA.
Proactive Cat Care with Basepaws
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