7 facts about vision that will surprise you
Miscellaneous / / July 08, 2022
Find out why the muscles of the eye are listed in the Guinness Book of Records and how many hours a day we lose due to blinking.
1. The retina of the eye is as unique as a fingerprint
Formation of the vascular pattern of the retina does not dependExplainer: Retinal Scan Technology / Biometric Update from genetics, so it is unique to each person. Even identical twins have different eyes. With fingerprints, the situation is similar, but they are more prone to mechanical injury: for example, a small cut on the pad will complicate fingerprinting. The retina is located inside the eye, so it is more difficult to damage it. Only certain diseases, such as glaucoma or cataracts, can interfere with identification.
In the eyes, there is another feature that is useful for establishing the identity - the pattern of the iris. Its color and texture inheritedExplainer: Iris Recognition / Biometric Update from relatives, but each person has his own pattern of grooves, recesses, screeds and other “ornaments”.
2. The eye distinguishes warm shades better than cold ones.
Color itself is a light wave that reflects off things. Depending on its length, the shade of the object also changes. For example, waveThe visible spectrum / Britannica at 400 nanometers it gives purple, and at 580 nanometers it gives yellow. If an object does not reflect at all, but only absorbs light, we perceive it as black.
A person receives information about color with the help of cones - photoreceptors on the retina of the eye. 60% of them handleCones / American Academy of Ophthalmology long waves: red, orange and yellow. Because of this, it is easier for the eye to distinguish between warm shades than cold ones - for this task, it simply has more resources.
3. If the eye were a camera, the resolution of its matrix would be 565 megapixels
At least that's the number in my calculations receivedNotes on the Resolution and Other Details of the Human Eye / ClarkVision scientist and photographer Roger M. Clark. So many megapixels is the maximum that a person could appreciate on one screen without noticing the division of the picture into fragments. For comparison: permission8K resolution: What it is and whether it's worth it / Smartframe 8K screen - only 33.2 megapixels.
However, human eyes themselves are nothing like cameras. To collect information, they are constantly on the move: receiveWhat is the resolution of the human eye? / Feel Good Contacts small fragments of the picture (about 7 megapixels at a glance) and send them to the brain, and already it sticks together the puzzle elements and creates a full-fledged image.
Although eyeballs are far from lenses, it is quite possible to replace their work with cameras. The development of neuroimplants that can restore the blind to the ability to see, are engaged Foundation for the Support of the Deaf-Blind “Connection” and the laboratory “Sensor-Tech”.
Their invention is called ELVIS. It consists of three components: a headband with two cameras, a belt with a microcomputer and an implant that is implanted in the visual cortex of the brain. The video signal from the cameras is processed by a computer and then sent to the brain like an impulse from the optic nerve. ELVIS should help partially restore vision to people with injuries or diseases of the retina, pathologies of the optic nerve and other conditions. The development will allow them to navigate in space, to distinguish between shapes and silhouettes.
4. Eyes see the world upside down
Vision is a complex process in which several "actors" are involved. First, the cornea refracts light and directs it through the pupil to the lens. That focuses light on the retina, and already it collects information and sends a signal to the brain through the optic nerve.
This process has one interesting feature. The cornea and lens are convex lenses that turn overOptical system of the eye / Russian ophthalmology online image: refracting through them, the rays of light converge at one point, and then diverge in the opposite direction. Therefore, the signals to the retina are inverted: the earth is above, and the sky is below.
It would seem that since the rays pass through two similar lenses, the picture should eventually become normal, but no. The lens is also a biconvex lens. When passing through the first wall, the image takes on its usual form, and through the second, it is again inverted. This principle of the eye as early as the 17th century provedR. S. fishman. The First Topographical Mapping of Vision in the Brain / JAMA Ophthalmology Rene Descartes, installing a screen instead of a retina in an amputated bull's eyeball. But you can verify this feature of the body at any time on your own. Just try to lightly press on the upper eyelid - a dark spot will appear below.
5. Squinting while sneezing is a protective reflex
Sneezing is a defensive reaction in itself. So the body gets rid of irritants settled on the nasal mucosa, such as dust or allergens. In the process, they fly out into the surrounding air space, which means that they can again end up not only on objects, but also on mucous membranes, including the eyelids. So that the fight against pathogens is not useless, the brain sendsCan you sneeze with your eyes open? / Science Daily a signal to the eyes to close - to eliminate all possible "entrances" for stimuli.
There is another theory. On it, we close our eyes due to muscle contractions: during sneezing strainsCan You Sneeze With Your Eyes Open? /SELF the entire face, including the muscles of the eyes.
By the way, sneezing with your eyes open is real - contrary to popular myth, they will not fall out. However, in addition to the probable return of stimuli there isCan You Sneeze With Your Eyes Open? /SELF tiny chance of getting an eyeball subluxation if you sneeze will beGlobe luxation: Causes and treatment / All About Vision very powerful.
6. A person spends an hour and a half a day blinking
This is 10% of the total waking time. Of course, if a person sleeps exactly 8 hours a day. On average, the eyes close 10-20 times per minute. And not only to moisten the eyeballs or get rid of a mote that has fallen on the mucous membrane. Brief stay in the dark helpsT. Nakano, M. Kato, Y. Morito, S. Itoi, S. Kitazawa. Blink‑related momentary activation of the default mode network while viewing videos / PNAS rest the brain. Even a fraction of a second is enough for him to stop focusing and relax a little.
Perhaps this mechanism may be the secret of the science of deception. When a person lies, he is less blinkingBlinking During and After Lying / Journal of Nonverbal Behavior - instinctively does not allow the brain to lose attention, so as not to get confused in its own lies.
7. Eye muscles are the most active in the body
Each eye has six. They are constantly in good shape to control the apple: hold it in place, turn it and make micro-movements for coordination - for example, move your eyes around the smartphone screen. And these muscles work synchronously in both eye sockets - to turn, for example, only one eye to the bridge of the nose, a person needs a lot of skill.
For an hour of active work with the text of the eye commitWhat is the strongest muscle in the human body? / Library of Congress about 10,000 movements. This is twice as much as doesHeart Beat / Cleveland Clinic heart. For such diligence, the eye muscles were even created page in the Guinness Book of Records.