How does a person perceive the world around him? The eyes are the organ of vision. A person receives the most information about the world around him
using vision.
Vision helps to distinguish
color of objects, their size,
shape, recognize, far
they are either close or moving
or motionless.
Age-related changes in vision
Class2
3
Decreased vision
3
3
Myopia
2-23%
2-39%
4
5
6
2
3
1
2-21%
- 25%
2-20%
7
8
9
4
4
6
1-20%
1-29%
1-23%
10a
10b
3
2
1-27%
4-37,5%
This is how a myopic person sees the world
To improve vision - glasses!
Rules for working with a computer:
1. The workplace must be autonomous, i.e. Notconnect other devices to the computer outlet.
2.The computer should be in a corner, because... exactly
The radiation from behind is higher than from the screen.
3.The monitor should not be exposed to direct sunlight
rays. Working with a computer should not exceed
2 hours a day, every 30 minutes a break for
rest.
4.The distance from the screen to the eyes is at least 50 cm.
5.In a room with computer equipment
Wet cleaning should be carried out daily. Hello!
My name is Kolya, I am 12 years old and I study at 6
class. I want to introduce you to mine
best friend is the computer. I'm with him
I practically never leave, I play a lot,
watching movies. It takes the most
place of honor in my room - next to
my bed. So that parents don't see
whether it is turned on or not (for some reason they really don’t care
like mine new friend), I put it
monitor to the window, and everyone else to
doors. Only one problem - the sun
interferes with play, but that's okay. The main thing is me
I'm not asking to go outside. For what? After all, football
you can play virtually.
Hygiene rules when doing homework:
1.Homework must be completedtake place in specially equipped
place.
2.The light should come from the left side.
3.The light source should only illuminate
work surface, and the lampshade should
hide the filament from view.
4.The power of the light bulb in the lamp should be
at least 60 watts.
5.The distance from the eyes to the book should be
40 cm.
It is forbidden!
It is forbidden!
It is forbidden!
To relieve fatigue, look into the distance...
Gymnastics for the eyes
1. Without turning your head, look awayto the left bottom corner, to the upper right, to
lower right, lower left corner.
Repeat 5 – 8 times.
2. With open eyes, slowly, to the beat
breathing, smoothly draw a figure eight in
space horizontally and vertically.
3. C with open eyes without turning
heads, write your name in space,
surname, first in small letters, and
then bigger ones.
Nourishment for eyes
Take care of your eyesight
Read and write only in good lighting, but remember that bright light should not enter your eyes.Make sure your book and notebook are
at a distance of 30 - 35 cm from the eyes.
When reading, place the book on an inclined stand.
When writing, the light should fall from the left.
Don’t read while lying down, in transport
Take care of your eyesight.
If you read, write, draw for a long time,every 20 minutes give your eyes
relax: never three eyes with your hands. So
you can introduce specks and dangerous
microbes Use a clean nasal
handkerchief, look out the window, into the distance, until
count to 20. Very harmful to the eyes
watch TV for a long time.
Don't be embarrassed to wear glasses.
Analyzers and sense organs
Analyzers
Analyzers are called systems that consist of receptors, pathways and centers in the cerebral cortex. Each analyzer has its own modality, that is, a way of receiving its information: visual, auditory, gustatory, and others. Excitations arising in the receptors of the organs of vision, hearing, and touch are of the same nature - electrochemical signals in the form flow nerve impulses . Receptors are strictly specialized. Each group of them is capable of perceiving and translating only a certain set of stimuli into a language understandable to the nervous system, that is, nerve impulses. There is no confusion because each nerve impulse goes to its corresponding area of the brain. Here, in the primary sensitive zones, the analysis of sensations occurs, in the secondary zones - the formation of images received from the sense organs of one modalities(for example, only from sight, or only from hearing or touch). Finally, in the tertiary zones of the cortex, images or situations received from sensory organs of different modalities, for example, vision and hearing, are reproduced.
Visual analyzer
The meaning of vision. Through visual analyzer a person receives the main amount of information. Objects and phenomena around us, our own body We perceive primarily through vision. Thanks to vision, we learn many household and work skills and learn to follow certain rules of behavior. This means that vision plays a primary role in the knowledge of the external world for a person. The ability to see beauty in the surrounding nature, in works of sculpture, architecture, painting, ballet, and cinema distinguishes a well-mannered person.
Structure of the eye. The eyes are equipped a large number auxiliary devices for their protection. This brows, thanks to which sweat flowing from the forehead does not get into the eyes. Eyelids and eyelashes protect eyes from dust. The eyelids constantly close and open (blinking), evenly wetting the surface of the eye with tear fluid. Tears are formed in lacrimal glands ah, located in the outer part of the orbit above the eye, excess tear fluid drains into nasal cavity through tear duct. The secretion of the lacrimal glands acts not only as a lubricant, but also as a disinfectant liquid. The eye is spherical in shape and is therefore called the eyeball. This shape allows it to move within certain limits in the cavity of the bone cavity - eye socket. Eye movement is achieved by contraction six eye muscles . They are attached at one end to the wall of the orbit, and at the other to the eyeball.
The outside of the eye is covered with a dense white tunica albuginea, which surrounds the entire surface eyeball. The tunica albuginea is connected to the mucous membrane, which covers the inside of the eyelids. Front tunica albuginea connects to the transparent shell - cornea. The other layer of the eye is vascular. It is permeated with many blood vessels, supplying the eye with blood. Inner surface This shell contains a thin layer of coloring matter - a black pigment that absorbs light rays. In front, opposite the cornea, choroid goes into iris, which may be different color depending on the amount of pigment contained in it. It is this shell that determines the color of the eyes. In the center of the iris there is a round hole - pupil. The pupil dilates or contracts depending on the amount of light falling on the eye. You can easily see this for yourself if you observe the pupil in the mirror and at the same time bring some light source, such as a lamp, to your face and move away from it. Finally, the inner wall of the eyeball is lined with a very thin membrane - retina. She has complex structure. It contains cells that are very sensitive to light - visual receptors. It is in them that the energy of light rays penetrating into the eye is converted into a process of nervous excitation. And along the fibers optic nerve these nerve impulses travel to the brain.
Retina has a thickness of 0.15–0.20 mm and consists of several layers nerve cells. The first layer of the retina is directly adjacent to the black pigment cells. This layer is formed visual receptors - rods and cones. In the human retina there are tens of times more rods than cones. The rods are excited very quickly by weak twilight light, but cannot perceive color. Cones are excited more slowly and only by bright light; they are able to perceive color. The rods are relatively evenly distributed across the retina. Directly opposite the pupil in the retina is yellow spot , which consists exclusively of cones. Therefore, a person most clearly distinguishes those objects whose images fall directly on the yellow spot. With the help of the eye muscles, we can control eye movement and change the direction of gaze. But always, when looking at a new object, the gaze moves so that the image of parts of the object sequentially falls on the macula. The nerve cells of the retina extend from long shoots. In one place of the retina they gather in a bundle and form optic nerve. More than a million of its fibers transmit visual information to the brain in the form of weak nerve impulses. The place on the retina from which the optic nerve emerges is devoid of receptors and is called blind spot. Every schoolchild can verify its existence with the help of a simple experiment.
Visual hygiene. Prevention of eye diseases
Vision hygiene. Many people develop myopia. If you follow simple rules, then in most cases you can prevent this visual impairment. It is very harmful to keep books and notebooks closer than 30 cm from your eyes. When we look at objects at close range, muscular apparatus the eyes become tense, the curvature of the lens changes, rapid fatigue and deterioration occur visual perception. With constant poor lighting and improper seating, you develop the habit of looking at everything up close. As a result, myopia develops. Staying in nature, where a wide horizon is provided, is a wonderful rest for the eyes. For normal operation Good lighting is important for the eyes. The study table should be placed closer to the window and so that the light falls from the left. On the left side of the desktop there is a table lamp with a 60-75 W bulb, protected by a lampshade so that the light does not enter the eyes, but illuminates only the book or notebook. Too bright lighting irritates the eyes and leads to rapid fatigue. It is harmful to read in moving vehicles, especially in poor lighting. Due to constant jolts, the book either moves away from the eyes, then approaches them, or deviates to the side. At the same time, the curvature of the lens either increases or decreases, and the eyes turn all the time, “catching” the elusive text. As a result, vision deterioration occurs. When we read lying down, the position of the book in the hand in relation to the eyes also constantly changes, its illumination is insufficient. The habit of reading while lying down harms your eyesight.
Eyes should be protected from injury. This is the most common reason clouding of the cornea (cataract) and blindness. The cause of eye injuries in children is most often pranks and fights. Some guys throw sticks, stones, and shoot with slingshots. All this can lead to eye injuries. In school workshops and factories, schoolchildren must strictly follow safety rules (use safety glasses, a screen, etc.). Do not blow away sawdust or shavings, as they may get into your eyes. When dust gets into your eyes, it irritates them. May be carried along with dust pathogenic microbes. The infection can get into the eye from dirty hands, an unclean towel, or a handkerchief. This may cause various diseases eyes, for example, inflammation of the mucous membrane - conjunctivitis, which often leads to deterioration of vision. Therefore, eyes must be protected from injury and from contact with foreign objects, dust, do not rub them with your hands, wipe only with a completely clean towel or handkerchief.
Visual impairment. One of important characteristics view is sharpness vision. Visual acuity determines the maximum ability of the eye to distinguish small details in the field of view. Visual acuity depends on the general illumination, the contrast of image details against a certain background and other reasons. The most common visual impairments are myopia and farsightedness. The presence of these disorders is determined by the doctor when measuring visual acuity using special tables. Myopia can be congenital or acquired. With congenital myopia, the eyeball has an elongated shape. Therefore, a clear image of objects located far from the eyes does not appear on the retina, but as if in front of it. Acquired myopia develops due to an increase in the curvature of the lens, which can occur due to improper metabolism or poor visual hygiene. Myopic people see distant objects as blurry. Glasses with biconcave lenses help ensure that clear images of objects appear accurately on the retina. Farsightedness It can also be congenital and acquired. With congenital farsightedness, the eyeball is shortened. Therefore, a clear image of objects located close to the eyes appears as if behind the retina. Acquired farsightedness occurs due to a decrease in the convexity of the lens and is most typical for older people. Farsighted people see close objects as blurry and cannot read text. Glasses with biconvex lenses help the appearance of an image of a nearby object exactly on the retina.
You cannot use someone else's glasses or choose glasses for yourself without a doctor's prescription. This leads to further deterioration of vision.
The meaning of hearing. The sense of hearing is one of the most important in human life. Hearing and speech together make up important tool communication between people serve as the basis for relationships between people in society. Hearing loss can lead to disturbances in a person's behavior. Deaf children cannot learn full speech. With the help of hearing, a person picks up sounds that signal what is happening in the outside world, the sounds of the nature around us - the rustling of the forest, the singing of birds, the sounds of the sea, as well as various pieces of music. With the help of hearing, the perception of the world becomes brighter and richer.
Ear and its function. Sound, or sound wave, is an alternating rarefaction and condensation of air, spreading in all directions from the sound source. And the source of sound can be any oscillating body. Sound vibrations are perceived by our hearing organ. The organ of hearing is very complex and consists of
· external,
· average,
· inner ear.
Outer ear comprises
auricle,
· ear canal.
Ears many animals can move. This helps the animal to detect where even the quietest sound is coming from. The human ears also serve to determine the direction of sound, although they are not mobile. auditory canal connects the outer ear with the next section - the middle ear. The ear canal is blocked at the inner end of the tightly stretched eardrum . A sound wave hitting the eardrum causes it to vibrate and vibrate. The higher the sound, the higher the sound, the higher the vibration frequency of the eardrum. The stronger the sound, the more the membrane vibrates. But if the sound is very weak, barely audible, then these vibrations are very small. The minimum audibility of a trained ear is almost on the border of those vibrations that are created by the random movement of air molecules. Means, human ear- a hearing device with unique sensitivity. Behind the eardrum lies the air-filled cavity of the middle ear. This cavity is connected to the nasopharynx by a narrow passage - auditory tube. When swallowing, air is exchanged between the pharynx and the middle ear. Changes in outside air pressure, such as in an airplane, cause unpleasant feeling- “stuffed ears.” It is explained by the deflection of the eardrum due to the difference between atmospheric pressure and pressure in the middle ear cavity. When swallowing auditory tube opens and the pressure on both sides of the eardrum is equalized. In the middle ear there are three small bones connected in series:
· hammer,
· anvil,
· stirrup
The malleus, connected to the eardrum, transmits its vibrations first to the anvil, and then the enhanced vibrations are transmitted to the stirrup. In the plate separating the cavity of the middle ear from the cavity of the inner ear, there are two windows, held together by thin membranes. One window oval, the stirrup “knocks” on it, another - round. Begins behind the middle ear inner ear. It is located in the depths temporal bone skulls The inner ear is a system of labyrinths and convoluted canals filled with fluid. The labyrinth contains the organ of hearing - snail. This is a spirally twisted bone canal that has two and a half turns in humans. Vibrations of the membrane oval window transmitted to the fluid filling the inner ear. And it, in turn, begins to oscillate with the same frequency. Vibrating, the liquid irritates the auditory receptors located in the cochlea. The cochlear canal is divided in half along its entire length by a membranous septum. Part of this septum consists of a thin membrane - membranes. It contains sensory cells - auditory receptors. Fluctuations in the fluid filling the cochlea irritate individual auditory receptors. They generate impulses that are transmitted along the auditory nerve to the brain.
Auditory perception . The brain distinguishes between the strength, height and nature of sound, and its location in space. We hear with two ears, and this has great importance to determine the direction of sound. If sound waves come to both ears at the same time, then we perceive the sound in the middle (front and back). If sound waves arrive a little earlier in one ear than in the other, then we perceive sound either on the right or on the left.
Related information.
Radobolskaya L.Yu., Radobolsky S.I.
VISUAL HYGIENE
HOW TO READ CORRECTLY?
It is extremely important that the light is correct during the reading process. This will protect your eyes from overstrain. When reading, the light source should be located above and behind the reader so that the light falls from behind the shoulder. It is forbidden to read if the light is shining into your face. The lighting of the room where a person is reading should be quite bright. You cannot read in the dark, as this will damage your eyesight. The desktop should be positioned so that a window or other light source is on the left. An artificial light source, for example, a table lamp, must be covered with a shade, since direct light rays will otherwise hurt the eyes. When reading with a table lamp on, it is also better to leave the main lighting on - this will create a smooth transition from less intense light to more intense light.
It is harmful to read in a moving car, since the text, as a result of shaking, is at different distances from the eyes. In visual hygiene, it is very important to maintain the correct distance between the eyes and the text, which should be at least thirty centimeters.
HOW TO WORK AT A COMPUTER CORRECTLY?
To relieve eye strain when working at a computer, it is recommended to do a few simple exercises. During work, the computer monitor should be located at least an arm's length away. In addition, the monitor should be positioned on the desktop in such a way that when you look up, you can see all the objects in the room. After forty minutes of working at a computer monitor, you need to take a break and perform light exercises, for example, frequent blinking, during which the eyes relax and are moistened with the secretion of the lacrimal glands.
GYMNASTICS COMPLEX FOR EYES
Horizontal eye movements: right-left. Movement of the eyeballs vertically up and down. Circular eye movements: clockwise and in the opposite direction. Intense squeezing and unclenching of the eyes at a fast pace. Movement of the eyes diagonally: squint your eyes to the lower left corner, then move your gaze upward in a straight line. Likewise in the opposite direction. Bringing the eyes to the nose. To do this, place your finger on the bridge of your nose and look at it - your eyes will easily “connect”. Frequent blinking of the eyes. Eye work "at a distance". Go to the window, look carefully at a close, clearly visible detail: a branch of a tree growing outside the window, or a scratch on the glass. You can stick a tiny circle of paper on the glass. Then look into the distance, trying to see the most distant objects.
PREVENTION
To prevent myopia, you need to expose yourself to ultraviolet rays. If there is a lack of ultraviolet rays, the metabolism of phosphorus and calcium in the body is disrupted. For this reason, the adaptive ability of the eyes is reduced. When exposed to sunlight, vitamin D found in cells skin, becomes active and normalizes the proper absorption of phosphorus and calcium compounds in the body.
PROPER NUTRITION
Plays a huge role in visual hygiene balanced diet, which should include the required amount of vitamins, in particular the “eye” vitamins A and D. Vitamin D is included in such products as beef liver and sea herring, egg yolk and natural butter. Vitamin A is extremely important for vision, as it is responsible for the eyes’ ability to see at dusk. With a deficiency of this vitamin, visual acuity is disrupted, the skin loses its tone, and becomes vulnerable to inflammatory processes. Vitamin A is found in abundance in cod liver, cream and chicken eggs. There is also such a substance as provitamin A, called carotene. Carotene is necessary in the human body for the synthesis of vitamin A. There is a lot of carotene in carrots and bell pepper, rose hips and onions, apricots and lettuce.
The work was prepared by: students of grade 11 “a”
Sirotina Svetlana Laskova Aksinya
Volzhsky 2013
importance of compliance
vision hygiene
1) Definition of the concept of visual hygiene
2) Factors affecting vision
3) Proper nutrition as a guarantee good vision
4) Rules for working at the computer
5) 5 golden rules
6) Conclusion
Every person must take care of their eyes
Vision hygiene is a set of measures aimed at preserving and maintaining good vision, preventing many eye diseases.
Vision hygiene
When working with high visual strain, it is necessary to periodically rest your eyes. You can also do an eye massage. Very
useful to look at nature , admiring the greenery and flowers. You can look into the distance, into the endless depths of the sky. This not only gives rest to the eyes, but also soothes nervous system, relieves stress.
Factors affecting vision
1) Balanced nutrition
2) Reading hygiene
3) Compliance with the rules of planting and lighting
4) Compliance with the rules when watching TV and working at the computer
Balanced nutrition: what foods do vitamins “live” in?
Vitamin A – fish, seafood, apricots, carrots, tomatoes, etc.
Vitamin B1 – rice, vegetables, poultry, etc.
Vitamin B2 – milk, apples, wheat grains, etc.
Vitamin C – rosehip, Bell pepper, black currant and so on.
Working rules for
computer
1) Choose correct posture. Namely: directly
opposite the screen, top part monitor at eye level or slightly below.
2) Maintain a distance from your eyes to the monitor -
3) Choose something convenient for working at the computer
4) The seat height of the chair (chair) should be
such that the hands placed on the keyboard are positioned horizontally.
5) Take breaks for 15-20 minutes every hour.
6) Watch your breathing: it should be
smooth, without delays.
7) Do exercises as often as possible for
Slide 2
- Ophthalmology is a science that studies the anatomy, physiology of the organ of vision, diseases related to the organ of vision, as well as the structure of blindness.
- The goals of ophthalmology are to minimize the number of blind and visually impaired people.
According to WHO, there are 42 million blind and visually impaired people in the world. Moreover, there is an increase in this indicator every year, and the increase is 3-6% per year.
Slide 3
- One of the important characteristics of vision is visual acuity.
- Visual acuity determines the maximum ability of the eye to distinguish small details in the field of view.
- Visual acuity depends on the general illumination, the contrast of image details against a certain background and other reasons.
- The most common visual impairments are myopia and farsightedness.
- The presence of these disorders is determined by the doctor when measuring visual acuity using special tables.
Visual impairment
Slide 5
In myopic eyes, the image is focused in front of the retina.
Slide 6
Myopic people it's hard to see route numbers public transport, read road signs, as well as distinguish other objects at a distance.
At the same time, nearsighted people can see well at close range.
- Up close
- In the distance
Slide 7
Causes of myopia
Excessive visual work at a close distance from the subject (without rest for the eyes and in poor lighting);
Hereditary predisposition, expressed in the structural features of the eyeball and metabolism in it;
Weakened sclera, which does not provide adequate resistance to excessive eye growth;
Insufficiently developed accommodative muscle of the eye, which is responsible for “tuning” the lens to different distances;
Overexertion of a weakened muscle.
Slide 9
In farsighted eyes, the image is focused behind the retina.
Slide 10
In people suffering from farsightedness, the accommodative muscle is constantly tense, which is why visual fatigue and headaches often occur.
Slide 11
Poor eyesight near;
Poor distance vision (with large degrees of farsightedness);
Increased eye fatigue when reading;
Eye strain during work (headaches, burning eyes);
Strabismus and “lazy” eyes in children;
Frequent inflammatory diseases eye (blepharitis, stye, chalazion, conjunctivitis)
Symptoms of farsightedness
Slide 12
If you are concerned about the symptoms of farsightedness, then you need to undergo a complete ophthalmological examination to clarify the characteristics of the pathology and choose a method of vision correction.
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