Cats are fascinating and adorable creatures. They are fiercely independent, curious, and loyal with a remarkable sense of sight. Studies have shown that they have better vision than the human eyes, especially at night. This is because cats’ eyes collect at least 50% more light. In this article, we’ll compare the cat’s vision with the human eye and discuss the details.
Before discussing the reasons for a better night vision, here’s an interesting fact about cats that you need to know!
“Cats can portray their emotions through their eyes. Whether they are blue, green, or gold, their eyes communicate emotions through physiological changes in pupil size and eyelid position”.
Can cats see in the dark?
Cats are adaptable to catch their prey at night for the following reasons:
- Photoreceptor cells (cells in the retina that respond to light), Rods, and Cones, play a significant role in determining the nocturnal capabilities in humans and cats. The elevated levels of sensitive rods in the retina help in improving night vision. Cat’s density of rods and sensitive receptors is three times that of human beings.
- While humans do not have an unobstructed vision at night because the cell layer on the retina called Pigment epithelium has dark spots and does not allow the light to be reflected. The substantial number of fibers in human beings make their vision better in daylight. Additionally, human eyes have more cons in place of rods and less sensitive receptors, weakening their nocturnal capabilities.
- The lens of the feline’s eye exists near the optic nerve, which helps cast a smaller but vivid or vibrant image on the retina. The compact size contributes to contracting the resolution, but the brightness increases the signal, which significantly improves their nocturnal status.
- Pupil dilation is another factor that contributes to improving the night vision of cats. At night, cats tend to increase their pupil size to feast on their prey. This property of cats also becomes active in case they sense any threat from other creatures.
- Eyes usually have the property of shining at any time of day. Some creatures have a unique reflective pattern called tapetum lucidum, which makes them seem extra shiny at night. It acts as a small mirror at the backside of many animals’ eyelids which helps them shine at night. Cats are also one of those creatures who possess this reflective pattern.
When the light enters through the eye, it usually passes through the retina (layer possessing cells that are sensitive to light). However, sometimes some light misses the retina and prefers to pass through its sides without touching it and meet the tapetum lucidum, which helps them to have good vision at night. This is also the reason that the cat’s eyes gleam at night. So the next time you see shiny objects at night, there is no need to be scared. On the other hand, humans do not have tapetum lucidum, and you could tell that by putting light in their eyes, and they won’t shine.
- Cats have bigger eyes in proportion to their body size. The distance between the pupil to the retina is relatively smaller as compared to human beings. So, it allows the light to travel quickly at night, which helps cats make their night vision better than human beings. Humans are diurnal creatures because their retinal illumination is five times less than that of cats.
- Cats and humans have the same sensitivity level at low light levels. As the rods are more active at the time of night and cats have more number of rods cells. So, it makes them see clearly at nighttime. One difference is the small peak at 560 nm at the cat’s spectrum, which has a more structured response towards the light frequency reflected by tapetum.
Egyptians had many myths about cats’ gleaming eyes at night. They thought that cats could store sunlight in their eyes which they employ at night to maintain their vision.
Some other properties related to cat’s vision
Ability to Distinguish colors
There has also been a question regarding if cats can differentiate between colors or not. Some would say that they can distinguish colors, while some thought it to be a wrong conception. So, research was done to resolve the conflict. Their abilities were tested at mesopic or photopic levels to have a hypothesis that cats distinguish wavelength by employing rods in concurrence with a single type of cone.
When taken to the laboratory to train them to differentiate between distinct colors, Cats were able to learn it quickly. The colors that were used to make them differ were yellow, cyan, orange, and cyan. They maintained the aptitude to differentiate when the color catalysts were kept at odds with a bright enough background to permeate the rods.
An experiment was also conducted to make the cat forget about colors by exposing them to light too bright for them (9000 cd/m2 for 5 minutes period) and then let them tell the difference. To one’s surprise, they were still able to tell the difference between red and cyan.
The final results asserted that cats possess more than one type of cone.
Ability to Protect their Eyes
Cats have fascinating ways to protect their eyes in case they face anything that could harm their eyes. God designed cats’ eyes in a unique way that could amaze anyone. Cats could narrow their eyes to protect their eyes from any external factors. Another factor that differs the human eye from a cat’s vision is that cats do not have to blink their eyes to maintain the dampness in the eye. This way, they could keep an eye on their prey for a considerable time until they finally catch them without being distracted.
Cats have a third eyelid called the nictitating membrane to retain the moisture in their eyes without blinking them. The nictitating membrane also acts as a defensive layer to help cats protect their eyes. It extends from the lower corner of their vision and spreads in the eye diagonally.
Effects of age and diseases on cat’s vision
Like human beings, cats could also experience changes in their eyesight. As cats’ eyes have the same structure as human beings, they also share the same disorders that they are affected with as they grow old. Age-related changes lead to defective vision in cats. The question might arise about how to know if the cat is facing vision loss. Well, there are many ways to tell if the cat is going through any eye disorder. It will walk more watchfully, or it might also knock into things.
There might also be a behavioral change. Cats might feel frustrated or stop playing like they used to. Other symptoms might also include squinting, change in pupil size, cloudiness, or water in the corners of the eyes.
Cats with healthy eyesight have fair and bright eyes. Their actions are agile. They sometimes fix their favorite spot for them and prefer sitting there. The eye pupils do not vary in size, and the eyes are clean with no tears in the eye corners.
One of the most common changes is lenticular sclerosis. It results in a change of eye color. The pupil becomes grey, which has no effect on eyesight.
Cataracts start affecting the cat’s eyesight when they are older. They impair cats’ vision especially when cats face bright light, and the pupil shrinks. It is an impairment in which the lens becomes clouded which leads to opaque eyesight and blurred vision. Other factors that take part in causing cataracts include electric shock, inflammation, poor diet, and penetrated lens.
Glaucoma is also a common disease among cats. In this disorder, excessive fluid in the cat’s eye stiffens the eyeball.
It is a photoreceptor disease in which the cells start breaking down, causing cats to lose vision.
Final Thought
Cats always seem most active at night. The thought that arises in the mind of a cat’s observer is what makes them find themselves treated in the dark so conveniently when humans couldn’t really observe that. That’s what has been discussed in the entire article. The surprising reason is that cats have amazing nocturnal abilities because of their specially designed eye structure. Their eye structure is not entirely different from human beings. However, some differences make cats and human beings nocturnal and diurnal creatures, respectively. Cats have many times better vision than human beings at night and therefore could perform many adventures even in the dark.