Sharks have corneas that are identical to our corneas. In fact, there's times when they use shark eyes to replace human eyes.
Apart from us Humans, dogs are the only species that can understand visual signals. Dogs use this capacity every time they interact with us, so they can understand our movements.
There is no way you can sneeze with your eyes open. This is an involuntary reflex to protect you from infections, bacteria and Germs that travel in your breath at very long speed.
Some pirates were convinced that wearing an earring would improve or even cure bad eyesight, as they believed that the precious metals in an earring possessed magical healing powers.
During a video interview an American soldier, prisoner in Vietnam, blinked his eyes in Morse code spelling Torture. This way the US Military found out how the Vietnamese were treating prisoners.
AT FIRST SIGHT
Some years ago, experts did a study that proved that when people see pictures of someone attractive to them, the pupils expand up to 50%. There should be a tool that allow us to measure that, right?
BORN THIS WAY
Our eyes are developed in stages. Most babies are born color blind. It is a temporary condition, and lasts just a few weeks before colors start to creep into what he sees.
Don't panic, but all blue-eyed people are not only relatives, but also inherited a mutation developed by an ancient common ancestor. 10,000 years ago everyone had brown eyes.
Our eyes can see 30 versions of gray according to the engineers that design the screens of ebooks. However, a lot of scientists say that actually we can see from 8 to 500 shades of gray.
LIGHT SENSITIVE CELLS
A light sensitive cell is a specialized type of cell found in the retina that is capable of visual phototransduction, that means that they can convert light into signals. Each eye contains 107 million light sensitive cells!
Color blindness is said to affect about one in 12 men and one in 200 women worldwide. However, most of these sufferers aren't completely color blind, which is actually a condition called achromatopsia, and refers to people who can only see in black and white or shades of gray.
Brown eyes are actually blue under the brown pigment. If your eyes are brown, you can go through a procedure and change it to blue color permanently. Only people with European ancestors have blue eyes naturally.
Impossible colors are the ones that the human eye can't see. They can be seen in especial conditions, for example, if you cross your eyes when you see two stripes, one yellow, one blue, put together.
A BILLION COLORS
Tetrachromat is how they call people that can see almost a billion colors, when the human average is one million. It's a condition that "affects" 1% of the world population, though is difficult to prove.
TWO DIFFERENT COLORS
Some people have two differently colored eyes by birth. This condition is known as heterochromia. Heterochromia occurs when a person has too much or too little melanin in the body; this is a compound that creates pigment and is found in animals and plants.
THE MOST COMMON
The most common eye color in the world is brown. Over fifty percent of the world's population has brown eyes, with nearly all individuals from Africa and Asia sharing brown eye color.
At the beginning of the nineteenth century it was discovered that any colour in the visible spectrum could be produced by some combination of the colours blue, green and red in what is known as additive color mixture.
CONSTANTLY IN MOTION
Your eyes are always active 24/7. Other parts need time to warm up. The eyes are constantly in motion; when people are working, driving, writing, reading, and even when they are falling asleep and fast asleep.
Your eyes are almost 1 inch wide and weigh 8 grams. Size and weight is very consistent across different ethnicities, they can differ in just a few millimeters but not much.
As we said, eyes never sleep. That is why out of all the muscles in your body, the eye controlling muscles are the most active.The movements of the eyes are controlled by six muscles attached to each eye, and allow the eye to elevate, depress, converge, diverge and roll
There is a blind spot in your eye where the optic nerve is attached to the eye. Some process in our brains interpolates the blind spot based on surrounding detail and information from the other eye, so we do not normally perceive the blind spot.
YOUR EYES DON’T GROW
The eyeball is the only organism which does not grow from birth. It is fully grown when you are born. When you look at a baby's face, you see mostly iris and little white. As the baby grows, you get to see more and more of the eyeball.
Tears have almost the same composition as saliva. The film of your tears is made up of oil, water, and mucus. The oil layer reduces evaporation to keep the eyes moist.
Only 1/6 of the human eye is exposed. In fact, skulls have evolved over the years to offer maximum amount of protection to the part of your eyes that are unexposed.
On average, your eyes see 24 million different images in your life. That's 400000 minutes if you want to see them again at a speed of one image per second.
The human eye can only make smooth motions. It can't switch from one end of sight to another. It has to do with perception and focus. That's why it's hard to focus on something that runs fast.
A retinal scan is a biometric technique that uses the unique patterns on a person's retina blood vessels. The iris has 256 unique characteristics, in comparison to only 45 in the fingertips. This is the reason retina scans are better.
There are over 2 million working parts in the eye. These include: Your eyelids, which offer protection for your eyes. The sclera and cornea, which cover and help protect the eye's interior. The tear film, which carries oxygen to the cornea and helps keep your eyes healthy and comfortable.
Blinking is the fastest movement of the entire body. It is possible to blink 5 times in a second, without you noticing. This feature allows tears to moisten your eyes properly.
SCREENS VS. PAPER
Have you noticed that you read slower from the computer than from a book? That's because the eye and brain have to process more light. On average, you read 25% faster on paper.
Your eyes can process 36000 bits of information every hour. That's 864000 per day and 315360000 bits in a year! Quite impressive! Human retina can transmit data at the same rate as an internet connection.
Accommodation is the process by which the vertebrate eye changes optical power to maintain a clear image or focus on an object as its distance varies. Your eye can focus on about 50 things per second.
Human eyes heal faster than any other organ. That's because most of it is covered in living cells, that are the ones that replace the wounded ones. It takes only a few minutes to recover from a scratch.
On average, we blink about 17 times per minute, 14,280 times per day and 5.2 million times a year. As we said, this is an involuntary movement and we don't notice it unless we focus on it.
CAMERA VS. EYE
The lens of our eyes works faster than a camera lens. The human eye also has a lot more pixels than your camera, about 130 million pixels. However, most of these "pixels" only see in black and white.
Human eyes start to develop after 2 weeks of conception. In fact, The brain is still developing while the eyes grow inside the womb, making it unable to process visual cues and images, leaving their vision fuzzy. Between weeks 11 and 14 babies can see light from outside the womb.
The perfect eye contact time is 4 seconds. It is enough to see what color eyes the other person have. It is said that eye color to be an important social tool, that can determine how you relate with others.
The jellyfish has twenty four eyes, all of them similar to human eyes. However, they use them differently. Since they have no brain, they can't focus. Their vision is always blurry.
NOT THEIR FAULT
Need glasses? Stop blaming your eyes! The blurry or poor vision is never caused by them. It usually occurs when there is something wrong in the visual cortex in the brain.
Those who are blind can see in their dreams but vaguely. The longer they lived without sight, the fewer pictures they see. However, they dream as they live: with a mixture of sensory experiences. They feel and listen.
Our eyes use about 65% of the brainpower. No other organ uses this much brainpower. This include areas that are multimodal (sight-touch or sight-smell, for example) like the superior colliculus and some visual association areas.
The images sent to the brain are backwards and upside down and the brain adapts them to what it knows. If you press gently the right bottom of your eye, you should see a black spot in the upper side, proving that the image has been flipped.
There's a common saying that goes "It's all fun and games until someone loses an eye". It comes from Ancient Rome as their wrestling matches only had one rule, and it was eye gouging.
The most highly evolved eyes are those of the mantis shrimp. It has five eyes that have 4 times as many color receptors as human eyes and they allow it even to see in ultraviolet.
When someone is depressed, it's common to say that he or she see the world monochrome and flat. Research actually proves that in depression, people see less contrast and dull colors.
We grow fresh eyelashes after every 5 months. Their color may differ from that of the hair, although they tend to be dark on someone with dark hair and lighter on someone with light hair.
The Colossal Squid is not only the biggest invertebrate animal. It also has the largest eye, with an average size of 27 cm. This record includes the entire history of the Animal Kingdom.
We often think that pirates wore patches to cover a wound, but actually they used them to adjust their eyes from above deck to below deck. It allowed one eye to be trained for bright and the other for dim light.
MANY YEARS AGO
Eyes began to develop 550 million years ago. There's no record of complex eye structures before the Cambrian period and they can be seen in the Burgess Shale and the Emu Bay Shale fossils.
The Mayans used to think that cross-eyes were beautiful and made efforts to ensure their children had cross-eyes. Mothers used to suspend objects between the two eyes of the babies to accomplish that.