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  • It's your second most complex organ after the brain, and it's responsible for 80%

  • of everything you learn. Yep, I'm talking about your spleen! No wait. It's your EYES!

  • Yeah. How many colors can they distinguish? And why do you have way more in common with

  • sharks than you think? Let's see!

  • But first I have this: Remember the TV show I Love Lucy? Well, what did Lucy's husband

  • Ricky Ricardo say when he met a guy on the street with five eyes? Give up? “Ay, ay,

  • ay, ay, ay…” Okay maybe you never saw the show. Let's move on.

  • - Your eye has over 2 million working parts! One million nerve fibers connect it to the

  • brain! As all the pieces work together, they process around 36,000 bits of information

  • per hour.

  • - The eyes see things upside down. The brain then interprets this information and flips

  • images for us. That's because the cornea is curved, and light bends when it goes through

  • it.

  • - Your eyeball is around the same size as a gumball you can get from a grocery store

  • gumball machine. The lens in the eye is the size of an M&M candy. It also has protein

  • filling. Mmmm!

  • - The human eye can distinguish 10 million colors. All of them are combinations of three

  • basic colors: red, green, and blue. Out of those 10 million, people see more shades of

  • green than any other color.

  • - Iris scans are way more individual than fingerprints. Compare these figures: your

  • fingerprint has 40 unique features, and your iris has 256! That's why biometric iris scans

  • are the present and future of security checks.

  • - If you put all the eyelashes you'll shed during your life in one line, it will be 98

  • feet long. It differs from person to person, but you lose on average 1 to 5 lashes a day.

  • Eyelashes live for about 5 months.

  • - The first creatures to have eyes were single-cell organisms some 550 million years ago. I wasn't

  • around then. Their eyes didn't look anything like ours: they were patches of photoreceptor

  • protein.

  • - Do you often get red eyes in photos? Blame your blood vessels. When the light from the

  • camera flash gets reflected, it lights up the blood vessels at the back of your eyes,

  • hence the red color.

  • - Your eye size and shape affect your vision. People with larger eyes are often nearsighted.

  • And those who have eyes a bit shorter than average are likely to be far-sighted. This

  • has to do with how eyes reflect light.

  • - Shark cornea is almost 100% the same as the human one. In the future, it might allow

  • scientists to use shark cornea proteins to create biomaterials for making cornea substitutes

  • for people. Yes, there's something fishy going on here.

  • - You can sunburn your eyes. Symptoms resemble those of skin sunburn plus blurry vision.

  • You can't put sunscreen on your eyes, (ouch) but remember to wear quality sunglasses for

  • UV protection.

  • - Everyone, even a person with perfect vision, has a blind spot. It's on top of where the

  • optic nerve meets the retina. You aren't likely to notice it unless you experiment on purpose.

  • Your brain fills in the missing data for you.

  • - 10, 000 years ago, everybody had just one eye colorbrown. The first blue-eyed person

  • was born as a result of a genetic mutation. If you have blue eyes, that was your ancestor.

  • You share him or her with 10% of the world's population. The most popular eye color is

  • still brown.

  • - Eye muscles are the fastest of them all. They enable your eyes to move at a speed of

  • 500 degrees per second. They can also focus on 50 different objects in just a second.

  • Many of the moves your eyes make are automatic. That's why you can see something on the periphery

  • without actually looking there.

  • - You blink around 15-20 times a minute, 20,000 to 30,000 times a day, and at least 7 million

  • times a year. Each blink lasts just a moment. And still, when you sum up all of them, it's

  • 1.5 hours daily. You blink more when you're talking and less when you're reading a book

  • or something from a computer screen. That's why in the second case, your eyes get tired

  • faster. Blinking helps your eyes stay clean and healthy.

  • - The resolution of the human eye is 576 megapixels. But before you throw away your expensive camera

  • (which is not nearly as good!), hear me out! The eyes only have that many color receptors

  • in a tiny spot in the center. You need to move them a lot to get the full picture.

  • - You never sneeze with your eyes open. It IS technically possible. But an absolute majority

  • of people have an autonomic reflex to shut their eyelids when they're about to sneeze.

  • That's how your body protects your eyes from all those nasty things that can jump out of

  • your nose. Is it pretty? No it's not (snot).

  • - An adult with healthy vision can detect a candle flame from as far away as 1.7 miles!

  • This distance could probably be even bigger if the Earth's surface wasn't curvy and there

  • weren't other sources of light and natural obstructions.

  • - New-born babies are color-blind. And even though the little ones make a lot of crying

  • sounds, they never really shed tears. The tear ducts only start properly functioning

  • when babies are somewhere between 4 and 13 weeks old. But yeah, they cry from day one.

  • - It also takes some time for babies to learn to see! In the womb, their eyes get ready

  • to distinguish shapes, some colors, and light. But right after birth, babies can only focus

  • on something that's very close to them, like a parent's face when they hold them. Learning

  • to focus properly, move eyes, and interpret visual information that goes from the eyes

  • to the brain takes time.

  • - "20/20" has nothing to do with perfect vision. It only means you can see as well as other

  • people from a distance of 20 feet. Those with the sharpest eye have 20/10 vision. It means

  • they can see from 20 feet what the average person would only spot from 10 feet.

  • - There is a gel-like fluid in your eyes. It makes up 80% of the eye and floats between

  • the lens and the retina. It helps your eye stay in shape and protects the retina. When

  • you're young, the fluid is as thick as "Jell-O." As you get older, it becomes more liquid.

  • Drain-o?

  • - Your eyebrows and eyelashes have important protective functions. The eyebrows stop sweat

  • and other fluids from getting into your eyes. Eyelashes don't let in moisture, dust, sand,

  • and other particles that are in the air.

  • And now, do you know how long eyelashes help camels survive in the desert? Nope, they don't

  • wink at travelers asking for water. The long eyelashes keep sand out of their eyes.

  • And since we've moved on to animals, some of them have pretty cool eyes, too!

  • - Ostriches have eyes that are as big as billiard balls. Each eye is also larger than the bird's

  • brain. No wonder they're the champions of the land animal kingdom when it comes to the

  • eye size. Huge eyes and a small brain might be the reason why ostriches run in circles

  • when they see predatorsnot the smartest tactics, right?

  • - The colossal squid has the largest eyes in the world - each the size of a soccer ball!

  • - Hamsters blink for the same reason as humansto get rid of dust and other unwanted

  • particles. But they only blink one eye at a time and keep looking around with the other

  • to stay alert.

  • - Geckos can distinguish colors 350 times better than humans. They can even see colors

  • at night and notice ultraviolet and green light. Since they don't have eyelids and can't

  • blink, they lick their eyes to clean them and keep them moist. Boy that's a tongue.

  • - Chameleons' eyes are cool and unique: these animals have 360-degree vision. Their eyes

  • can also function independently. It means they can switch from binocular to monocular

  • vision, for example, when they hunt.

  • - Many insects, including bees, dragonflies, and wasps have 5 eyes: (Hey Ricky!) 2 on the

  • sides and 3 more set in a triangle on top of their heads. They use the extra eyes to

  • detect light and spot upcoming threats.

  • - Some fish also have more than two eyes. With four eyes, Anableps can see above and

  • below water at the same time! The box jellyfish go even further - these creatures have 24

  • eyes. They help them navigate under the water without bumping into things. Sadly the other

  • fish tease them: “Hey 24 eyes!” ha ha ha!

  • Hey, if you learned something new today, then give the video a like and share it with a

  • friend! And here are some other videos I think you'll enjoy. Just click to the left or right,

  • and stay on the Bright Side of life!

It's your second most complex organ after the brain, and it's responsible for 80%

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