What is vision? Vision is the ability of a person to see objects of larger and smaller sizes in the same conditions. It has been established in medicine that a person with vision without any deviations can distinguish objects and details located at a visual angle of 1 minute between them. This vision is considered 100%. Very rarely there are people with a vision of 200%, even less often - with a value of 300%.
World record human visual acuity
In 1972, the University of Stuttgart set a record within its walls that had not been recorded anywhere before. Student Veronica Seider surprised everyone with her eyesight, exceeding the ideal vision of the average person by 20 times. She was able to see and recognize a person by facial features at a distance of about 1600 meters.
Can visual acuity be affected?
Scientists and doctors of ophthalmological sciences have been trying to answer this question for many years in a row.
And in the end they came to a singledecision that through special training it is possible to increase visual acuity by 2-3 times. Of course, it is unlikely that the record will be broken, but the visual apparatus will significantly improve its work. Much more effective exercises for "pitching" vision for children. Because their visual muscles, like many others, are more elastic than those of adults.
What should a person's ideal vision be like
The vision of the average person on the planet is 1.
This number represents 100% vision. Normally, such a person can see two points in separate places, located at an angle of 1 minute between them. To determine visual acuity in medical terminology, the numbers 0, 1, 1, 2 are used. In one human eye there are over 120 million light-sensitive cells. The cerebral cortex decodes the information coming from the cells and produces it in various shapes and colors.
The retina of the human visual apparatus consists of rods and cones. The former are responsible for the ability to see gray in low light, and the cones are responsible for colored objects and details. Perfect vision is easy to confirm, for this you need to visit the office of an ophthalmologist. The specialist will invite the person to consider special tables and symbols. It is very important that it is the tables hanging in the doctor's office that can determine visual acuity, but not pictures from the Internet on a computer that "promise" to give an accurate result.
Which tables are used to test visual acuity?
Today there isseveral types of special tables, thanks to which it is easier for a doctor to determine how well or poorly a person sees.
- Golovin's table. This option consists of identical rings. They have holes in different parts of the "body". The specialist points out to the patient the rings that the person should consider, the patient should sit at a distance of 5 meters from the table.
- Snellen table. It is used mainly in English-speaking countries. This table consists of 11 rows. The very first line contains one large letter. In each subsequent line, the size of the letters decreases, and their number in a row increases.
- Orlova's table. It is used to test visual acuity in children. Here, instead of rings or letters, icons in the form of animals and plants are used. Normal vision is considered when a child sees the tenth line, sitting at a distance of 5 meters from the table.
Sivtsev's table. This is the most common type of perfect vision test. This table consists of the letters of the Russian alphabet, arranged in 12 lines. In the very top line, the letters are large, the lower, the smaller they are. Perfect vision 0 is when a person manages to recognize the letters from the tenth line from a distance of 5 meters
Deviations in the work of the visual apparatus
The most common visual impairment is myopia. In medicine, it is called myopia. Such a disease is characterized by the ability of a person to see only objects, objects and details that are nearby. Far away he can'tconsider. Also characteristic of myopia is an increase in the eyeball. This pathology can be both acquired and received during childbirth, that is, congenital. The main symptoms of myopia:
- poor distance vision;
- while the near remains normal;
- objects during their inspection can merge into one object, the image is distorted.
There are times when a person develops false myopia, in which case medication can help.
Another pathology in the work of the visual apparatus is hypermetropia. This disease is characterized by perfect distance vision and poor near vision. The main symptoms of hypermetropia:
- seeing objects as if in a fog;
- sometimes strabismus may develop;
- eyes get tired quickly;
Hypermetropia can be functional, normal and pathological.
What is astigmatism?
An equally complex disease of the visual apparatus is astigmatism. It is often combined with myopia and hypermetropia. Astigmatism is characterized by a violation of the sphericity of the lens and cornea. This pathology can be congenital or acquired. Congenital astigmatism is often diagnosed in childhood, and in adulthood it does not affect visual acuity in any way. But this is only in cases where the sharpness is not higher than half the diopter. When the pathology has more than one diopter, this indicates that vision is deteriorating. The visual apparatus needs urgent treatment. Acquired astigmatism often results from scarringcornea.
What is the ideal vision for children?
The eyes are a paired organ that is formed before the age of 18. Vision, in turn, can be stable, but it can also change throughout a person's life. Children from birth to the first year of life experience the formation of the visual system.
After birth, only an experienced specialist can check the reaction of the pupil to light. By the age of one, children begin to distinguish familiar objects well. Distinguish them in shape and color from each other. After the age of two, a small person begins to see everything more perfectly and learn to distinguish the distance between objects. When a child goes to kindergarten, the load on the visual apparatus increases. In order to maintain perfect vision of the child during this period, it is necessary to take breaks between loads on the eyes, allowing them to rest.
Interesting features of the physiology of vision
These are real facts that not everyone knows about;
- In ancient times, people checked visual acuity in this way: they looked at the sky at night, found the Big Dipper, then examined a small star in the handle of the bucket. This was evidence that the visual apparatus was working properly.
- The weight of one human eye is approximately 7 g and the diameter is 24 mm.
- Carrots can improve eyesight. This is absolutely true, vitamin A, which is found in this vegetable, helps maintain the full functioning of the visual apparatus.
- More than 90% of people in the world are born with gray-blue eyes. Closer to the second year of life, an eye color is formed that will remain forever.
- Green eyes are the rarest in the world. Only 2% of people have this color of the iris.
- Poles, Swedes, Finns are considered the brightest-eyed nations, and Turks and Portuguese are considered the darkest-eyed.
- In 1% of people on the planet, the color of the iris of one eye is different from the color of the other. Such people tend to have unusually high intelligence and can be very talented.
- Men blink twice as much as women.
- You can't sneeze without closing your eyes.
