The eye is the most important of the human senses, with the help of vision we get 90% of the information from the world around us. The eyes are a complex optical device and their main task is to transmit an image through the optic nerve to the brain for further processing.
At the same time, it is a unique structure and not yet fully explored human organ. But to date, scientists have discovered many of its secrets, and professional doctors perform operations of unimaginable complexity.
30 facts about human vision:
1. A person’s pupils dilate by almost 50% if he looks at a person for whom he feels strong sympathy;
2. Human eyes are able to distinguish approximately 500 shades of gray;
3. Each eye contains 107 million light-sensitive cells;
4. The eyes focus on about 50 objects per second;
5. Blinking will last about 100-150 milliseconds, and you can blink 5 times per second;
6. The eyes process about 36,000 pieces of information every hour;
7. You will not be able to involuntarily sneeze with your eyes open;
8. The shark’s cornea is as similar as possible to the cornea of human eyes, so surgeons use it as a donor material during operations;
9. About 10,000 years ago, all people on the planet had brown eyes, until a person living in the Black Sea region developed a genetic mutation that led to the appearance of blue eyes;
10. Brown eyes are actually blue, but under a brown pigment. There is even a laser procedure that allows you to turn your eyes from brown to blue forever.
10-min.jpg11. Every 12th male representative is colorblind;
12. All children, when they were just born, are colorblind;
13. The eyes of a baby do not produce tears until they reach the age of 6-8 weeks;
14. The human eye can distinguish only three colors: red, blue, and green. The remaining shades are a combination of these colors;
It is interesting to know! The Maya considered strabismus attractive and tried to provide their children with strabismus.
15. The diameter of our eyes is about 2.5 cm, and they weigh about 8 grams;
16. The eyes of a human will remain the same size as at birth, and the ears and nose will not stop growing;
17. Only 1/6 of the eyeball is visible;
18. On average, over a lifetime, a person sees about 24 million different images;
19. Human finger prints have 40 unique characteristics, while the iris of the eye has 256!Therefore, retinal scanning is used for security purposes;
It is interesting to know! Schizophrenia can be detected with up to 98.3 percent accuracy using a routine eye movement test.
11-min.jpg20. A person blinks an average of 17 times a minute, 14,280 times a day, and 5.2 million times a year;
21. The optimal duration of eye contact with the person you first met is 4 seconds. That’s how much it takes to determine what his eye color is;
22. The images that are sent to the brain are actually inverted;
23. The eyes use about 65 % of the brain’s resources— more than any other part of the human body;
24. “Wriggling” particles that appear in the field of view are called “floating opacities”. These are shadows cast on the retina by tiny strands of protein inside the eye;
25. Human dogs are the only ones who look for visual cues in the eyes of others, and dogs do this only by communicating with people;
26. The human eye can make smooth (non-intermittent) movements only if it follows a moving object;
27. A person “sees with the brain”, not with the eyes. In many cases, blurred or poor vision is not caused by abnormalities of the eyeballs, but by problems with the visual cortex of the brain.
28. Some people are born with eyes of different colors. This phenomenon is called heterochromia;
29. Diabetes is often diagnosed during a visual examination – type 2 diabetes is often detected during a visual examination in the form of small hemorrhages from the blood vessels at the back of the eye. This is another reason to check your eyesight regularly;
30. People with blue eyes see better in the dark than people with brown eyes.
Unusual features of human vision
A significant lack of human vision is the so-called dead zone-objects located next to each other, when focusing on them, 13-min.jpg suddenly, in some way, they begin to “disappear”. In fact, of course, they do not disappear anywhere: just their eyes stop seeing. Maybe that’s why car accidents happen so often?
In each eye of a healthy person, there is an area of the retina that is not sensitive to light, which is called the blind spot. The blind spots in the two eyes are located in different places, but symmetrically. This fact, as well as the fact that the brain corrects the perceived image, explains why when using both eyes, they are invisible.
Check for yourself: the picture below shows a red cross and a blue dot. Close your left eye and look only at the cross with your right eye. Out of the corner of your eye, you can also see the dot. Now, slowly move closer to the monitor. At some point, the blue dot will disappear altogether!
It is interesting to know! The eyes of the octopus do not have a blind spot, these organisms developed separately from other vertebrates.
Each person has a dominant eye that has a wider field of view.
It is interesting to know!80% of people in the world have the dominant right eye.
To determine the dominant eye do the following:
Connect your palms in such a way that you get a “triangle”.
Select an object a meter away from you and look at it through this triangle.
Close your right eye and then your left.
The dominant eye will see the object completely, without displacement, and the other eye will only see part of the object.
The residual image
Human eyes have three types of receptors that perceive three primary colors: red, green, and blue. If you look at the color image for too long, the receptors will get tired. Abruptly replacing this zhekartinku in black and white-the receptors will not have time to adapt, as a result, you will think that you see a color image.
The vessels of our eyes
For this experiment, you will need a small piece of paper with a hole in it. Place the paper in front of the bright white monitor screen. Look straight through the hole and shake the sheet slightly. After a while, you will see a dark grid of lines, reminiscent of the network that we see on the leaves of a tree — these are the vessels and veins of the eyeball, or rather, the shadow they cast.
It is interesting to know! Approximately 2% of women have a rare genetic mutation, due to which they have an additional cone of the retina. This allows them to see 100 million colors.
To conduct this experiment, you need to turn on the TV or radio with white noise or interference, place the halves of the ping-pong ball on your eyes and look through them at the light, take a horizontal position.
After a while, the method will begin to work and the person will experience vivid and complex hallucinations. So some can see horses, other animals, or even talk to relatives who are not alive.
But it is necessary to take into account that this experiment will be interesting only to persons with a developed imagination, who most often see vivid and memorable dreams.