First, let me provide an overview of how light waves are transduced into neural messages. Light waves enter the eye through the cornea, the protective field around the eye. Then it travels through the pupil and then the lens. The lens cause the light to bend in a process called accommodation. If the lens properly accommodate light, the image will land on the retina. Transduction occurs in the rods and cones of the retina. When the light goes into the retina, it passes through its rods and cones. From there, the electricity of the light sets off the action potential. After the rods and cones, the horizontal, bipolar, and amacrine cells pass coded visual information to the ganglion cells whose axons leave the eye and form the optic nerve. The optic nerve conveys the information to the thalamus, which is then distributed to the visual cortex of the occipital nerve. And, viola! We see!
In a new set of images, artist Nickolay Lamm tried to capture the differences between cat vision and human vision. A stunning photograph of cat versus human vision at night is below:
So, now I will accompany the pictures with differences between human eyesight and that of a cat's. First, cats have a wider field of view — about 200 degrees, compared with humans' 180-degree view. Cats also have a greater range of peripheral vision, all the better to spot a mouse (or toy) wriggling in the corner.
Cats are crepuscular, meaning they are active at dawn and dusk. This may account for why they need such good night vision. Their eyes have six to eight times more rod cells, which are more sensitive to low light, than humans do. In addition, cats' elliptical eye shape, larger corneas and tapetum, a layer of tissue that may reflect light back to the retina, help gather more light as well. The tapetum may also shift the wavelengths of light that cats see, making prey or other objects silhouetted against a night sky projected more prominent. Their extra rod cells allow cats to sense motion in the dark, much better than humans can.
However, felines don't have the advantage in all areas. The human retina has about 10 times more cones than cats' eyes have. Humans also have three types of cones, allowing them to see a broad spectrum of colors, with sensitivity peaks at red, green and blue. While cats may have three types of cones, the number and allocation of each type varies. In behavioral tests, cats don't seem to see the full variety of colors that most humans do.
Some experts believe cats' color vision is limited to blue and grays, while others believe it is similar to dogs', but with less intensity of hues and saturation of the colors. A colorblind person would see the same spectrum of colors a cat sees. On a side note: dogs see the world in fewer hues than humans do and cannot recognize the differences between red, yellow, green and orange objects. Fish, in contrast, can see ultraviolet wavelengths that humans can't see.
Humans also can see with much greater resolution and with a greater scope of vivid colors, due to their eyes' many cones. Humans have better long-distance vision, while cats are near-sighted.
Simply put, there are many advantages in vision in the eyes of cats and humans. But since we are not transforming into cats anytime soon, let's appreciate the perks we have.
Have a nice weekend, folks.
Sources:
http://www.livescience.com/40459-what-do-cats-see.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+Livesciencecom+(LiveScience.com+Science+Headline+Feed)
http://www.independent.co.uk/news/science/impurrfect-vision-images-reveal-the-differences-between-cat-and-human-eyesight-8884584.html
I hate cats but that's still super cool! If cats have such good version then why do they get hit by cars so much. They should take their vision and use it to benefit them selfs. Not that I mind the cat dying.... Lol
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