How We See: Eye Anatomy And Function
Eyes
Your eyes are among the most valuable of all your possessions. For that reason, they ought to have fairly frequent examinations by competent persons to make certain that they are free from disease and capable of doing an efficient job.
And a good eye examination, such as vision or dimming of vision, double vision, redness and the lid and symptoms and without changes, must be difficult to detect such signs of pain or swelling and inflammation. Sties of inflammation of the lid and, in common with difficulties crusting of the lid. Discomfort in the eyes of overwork, wrinkled and symptoms of dizziness and fatigue, rubbing his eyes and blink frequently, may lead to a similar job or not.
Some people quite obviously use only one eye, and turn the head to make that eye more effective. Other people hold the head in an unusual position in order to see better. This is due to the fact that they do not see objects in the normal positions. When there are crossed eyes or eyes that do not focus together properly the difficulty is easily apparent.
The inability to see distant objects, is another indication that there have been changes. In fact, if people keep reading material or other good work unusually close or unusually far from the eyes they should be an immediate investigation, probably with the intention of glasses to ensure that meet their needs. Stumbling people who tend not clear about objects in its path, or can appreciate the amount of steps. They get their fingers caught in machinery. They have car accidents. They fall down. Good eyesight countless unnecessary accidents prevented.
Development Of The Eyes
We depend so much on our eyes that we ought to give ourselves every benefit that we can in relation to their education, their hygiene, and their control. Here are some interesting facts about the development of the eye from birth.
The eye of the newborn child is about 70 per cent of the size of the eye of the person fully grown. It is a shorter eye than the eye of an adult; the lens of the eye of the newborn child is a sphere or circular globe. During the first few years of life the eye grows rapidly, and it reaches adult size at about the age of eight or nine years. The lens of the eye continues to grow throughout life. The pupil of the eye is small at birth and remains small until about the end of the first year. During childhood and up to the age of youth the pupil of the eye develops its maximum size. Then it gradually becomes smaller, so that in older people the pupil depends to a large extent on the adaptation of the retina of the eye to light.
The retina is the nerve tissue at the back of the eye by which we are able to see. If a great deal of light suddenly pours into the eye the pupil will become smaller by contracting. Gradually the retina will adapt itself to the increased illumination. Then the pupil will again enlarge to approximately its normal size. There are, however, many different factors which may modify the size of the pupil from time to time.
The iris is the eye color part. Dark race than the blonde blue-eyed people have a race of people iris darker color. Most children are born with a blue iris, the color is due to the appearance in the color layer of the iris. Material life as the first few years, the color change becomes thicker. Then, the eyes may become brown or even dark. If there is a lack of eye pigment has a strange color, like pink is the bleaching to see. As children grow, eyes become longer. The retina is far back, the lens becomes flat. This occurs primarily 6 to 16-year-old children.
If the rays of light which enter the eye focus short of the retina the child is nearsighted. If, for example, the eye of the child focuses normally at the time of birth, it is sure to become nearsighted as the eye becomes longer.
The lens in children is quite flexible, but as people grow older this flexibility tends to decrease. It is apparent, therefore, that parents should have the eyes of children tested regularly, to make certain that they are getting the best vision possible with the type of eyes they have at the time they are born.
Children must also learn to properly use their eyes. This includes coordination of nerves and muscles and the brain, which can be improved with proper training. If the child is older it is developed, what the experts
Mechanism Of Vision
We do not see the eye, but the brain and nervous system. To see the main factors involved in the optic nerve and visual centers in the brain. Followed by the retina, the back of the eye tissue, which is a part of the nervous system, because it brings out what is regarded as the optic nerve. The lens is actually a lens, and help to focus on the retina of the object. Muscle control in their size and shape of the focusing lens. There are supporting muscles that move the eye. Iris is the most students. By expanding and contracting, the iris control the amount of light entering the eye.
The eye can adapt itself to various conditions of light, but even this mechanism of adaptation may be exhausted by overuse. It is better to provide suitable lighting than to strain the eye by insufficient light. The eye may also be strained by too much badly distributed light or glare. The effects of glare and of eyestrain result in the fatigue of the eye, with increased danger of accident.
Devices for measuring the amount of light in use at any point in the office, the shop, or the home are now available. Shades are made to distribute light suitably and thus prevent glare. Walls are painted and ceilings enameled to reflect a maximum amount of good light where it?is most needed. Attention to these factors may mean many more years of good vision for those who otherwise would soon be incapacitated. An eye which is fatigued and unable to work satisfactorily becomes easily irritated. Moreover, it is more likely to be invaded by foreign bodies like cinders and dust, simply because the tissues do not react to get rid of such foreign material. People with bad eyesight frequently have red rims on the eyes, swollen eyelids, and constant watering. The eyelids will be crusted together in the morning.