Contents
- Your irises are one of a kind
- How you feel affects what you see
- Each of us was color blind
- Blue eyes are actually the result of a mutation
- The cornea – one of a kind
- Flashes of flashlights
- But how is it… upside down?
- Do you know what resolution you see?
- Why are night vision goggles green?
- Brown-eyed newborn – is it possible?
- The most active muscles
- Myopia or farsightedness depends on the shape of the eye
Our eyes are one of the most fascinating and complex parts of the body. But we bet you don’t know how amazing they really are – here are 12 amazing facts and fun facts about the eyes that will make you appreciate them even more!
Your irises are one of a kind
Most of us think that the most unique part of the body is the fingerprint – nothing could be further from the truth. While the fingerprint has around 40 unique features, our retina has as many as 256. For this reason, retinal scans, which use infrared light to map the unique pattern of blood vessels on the retina of the eye, are becoming increasingly popular during security checks. Interestingly, even identical twins that share DNA do not have identical irises. [1]
How you feel affects what you see
For those struggling with depression, saying that the world appears black and white can be more than a metaphor. Research has shown that people with severe depression experience visual impairment and measurable differences in contrast perception, supporting the thesis that mental health can affect how we perceive our surroundings. [2]
Each of us was color blind
Everyone in the world is born color blind! At birth, babies only see black, white, and some shades of gray because some of the nerve cells in their retina and brain are not fully developed. The baby begins to see the first colors after about three weeks of life – first he distinguishes between red, then green, yellow and blue.
Blue eyes are actually the result of a mutation
All people with blue eyes have a common ancestor. Scientists believe that about 6-000 years ago, a genetic mutation took place that caused the world’s first person to be born with blue eyes. So it can be said that every blue-eyed person has a very distant but common relative! [10]
The cornea – one of a kind
The cornea is the only tissue in the human body that does not contain blood vessels. Why? The cornea must remain transparent to refract light properly. If blood vessels were present, they would interfere with this process. Blood vessels in the cornea of the eye appear only in the course of certain diseases, such as the failure of the corneal epithelial stem cells. [4]
Flashes of flashlights
“Red eye” appears in photos because light from the flash is reflected from the back of the eye. The choroid behind the retina is rich in blood vessels, which sometimes makes it appear red in photos. [5] Red-eye is also affected by the amount of melanin – people with less melanin will reflect more light, which explains the frequent occurrence of this effect in albinos.
Although the cause of this effect lies in the structure of the eye, some cameras can reduce the red-eye effect by firing a few preliminary flashes before the final flash to give the pupil enough time to constrict and adjust to the increased light conditions. [6]
But how is it… upside down?
While it is true that we see with our eyes, the retina is actually part of the brain. When light strikes the retina, it is transmitted as electrical impulses to the optic nerve and from there to the brain, where the 2D image is converted into a 3D image upside down. Incoming electrical impulses are separated and analyzed in different parts of the brain and then rotated again. [7]
Do you know what resolution you see?
If one of our eyes were a digital camera, it would be 576 megapixels. For comparison, some of the best cameras in the world are around 50 megapixels.
Why are night vision goggles green?
Night vision goggles are green because the human eye can distinguish more shades of green than any other color. What’s more, the green color has negligible impact on vision and is less tiring to the eyes – this is of great importance especially in military conditions, where long-term observations are carried out. [8]
Brown-eyed newborn – is it possible?
Most newborns have light blue eyes, and their color changes over the months of life, which is associated with the start of melanin production in the iris of the eye. Melanin is a type of pigment that gives color to the eyes, skin, and hair. The final color of the baby’s eyes can only be seen in the third or fourth year of life. [9]
The most active muscles
Of all the muscles in the human body, the muscles surrounding the eyes are the most active. Although the eye muscles are not particularly strong, they are extremely fast and precise! The muscles that surround the eye include six small muscles that control the eye itself (called the extraocular muscles), and one that moves the eyelid. Inside the eye, in turn, there are muscles that narrow and dilate the pupil and help the eye focus on nearby objects.
Myopia or farsightedness depends on the shape of the eye
People with myopia – the most common vision problem, have elongated eyeballs, which means that when looking into the distance, light is focused in front of the retina. In people with farsightedness, the eye is too ‘short’, which means that the focus on nearby objects is behind the retina.