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  • Hello everyone.

  • As you all know, eyes provide organisms vision, the ability to process visual detail, as well

  • as enabling several photo response functions that are independent of vision.

  • As you are watching this video, have you ever considered how this video would look like

  • if you were a cat?

  • Well, in this video, we are going to look at how the internet's favorite subject sees

  • the world.

  • The biggest difference between human vision and cat vision is in the retina, a layer of

  • tissue at the back of the eye that contains cells called photoreceptors.

  • The photoreceptors convert light rays into electrical signals, which are processed by

  • nerve cells, sent to the brain, and translated into the images we see.

  • The two types of photoreceptor cells are known as rods and cones.

  • Rods are responsible for peripheral and night vision, where they detect brightness and shades

  • of gray.

  • Meanwhile, cones are responsible for day vision and color perception.

  • To put it in simpler words, you see a lot of colors if you have a lot of cones.

  • And you can see better in the dark if you have a lot of rods.

  • Cats actually have a high concentration of rod receptors and a low concentration of cone

  • receptors.

  • Humans have the opposite, which is why we can't see as well at night but can detect

  • colors better.

  • Now let's take a look at the visual field.

  • This refers to the area that can been when the eyes focus on a single point.

  • It includes what can be seen straight ahead, as well as above, below, and to the side.

  • As you can see, cats have a slighter wider visual field of 200 degrees compared to the

  • average human visual field of 180 degrees.

  • But, in the aspect of visual acuitty, which is the clearness of vision, the average human

  • has a visual acuity of 20/20.

  • A cat's visual acuity is anywhere from 20/100 to 20/200, which means a cat has to be at

  • 20 feet to see what an average human can see at 100 or 200 feet.

  • This is the reason why cats seem to be nearsighted, which means they can't see far objects really

  • well.

  • The ability to see close objects would be well-suited for hunting and capturing prey.

  • As you probably already noticed, the way cats see colors is also quite different from humans.

  • It's a common misconception that cats can't see any colors, only shades of gray.

  • Humans are known as trichromats, meaning they have three kinds of cones that allow them

  • to see red, green, and blue.

  • Cats are also thought to be trichromats, but not in the same way that humans are.

  • A cat's vision is similar to a human who is color blind.

  • They can see shades of blue and green, but reds and pinks can be confusing.

  • These may appear more green, while purple can look like another shade of blue.

  • Other than that, cats also don't see the same richness of hues and saturation of colors

  • that we can.

  • Even theough cats can't see fine detail or rich color, but they actually have a superior

  • ability to see in the dark because of the high number of rods in their retina that are

  • sensitive to dim light.

  • As a result, cats can see using roughly one-sixth the amount light that people need.

  • Cats also have a structure behind the retina, called the tapetum, that is thought to improve

  • night vision.

  • Cells in the tapetum act like a mirror, reflecting light that passes between the rods and the

  • cones back to the photoreceptors and giving them another chance to pick up the small amount

  • of light available at night.

  • This is what makes cats' eyes glow in the dark.

Hello everyone.

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B1 中級

猫の世界の見方 (How Cats See The World)

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    Evangeline に公開 2021 年 01 月 14 日
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