1. The ocular wall is mainly divided into outer, middle and inner layers.
The outer layer consists of cornea and sclera.
The anterior 1/6 is transparent cornea, and the other 5/6 is white sclera, commonly known as "white eyes". The outer layer of eyeball plays a role in maintaining the shape of eyeball and protecting intraocular tissues. Cornea is the highest entrance to receive information. The cornea is the transparent part in front of the eyeball, through which light enters the eyeball. The cornea is slightly oval and slightly forward. The transverse diameter is11.5-12mm, and the longitudinal diameter is about10.5-1mm. The peripheral thickness is about 1mm, and the center thickness is 0.6 mm The tear film in front of the cornea can prevent the cornea from drying and keep the cornea smooth and optical properties.
Corneal nerve is rich and sensitive. Therefore, the cornea is not only the main structure of light entering the eye and refracting imaging, but also plays a protective role and is an important part of measuring people's perception.
Scleral is a compact collagen fiber structure, opaque, milky and tough.
The middle layer, also called uvea and pigmented membrane, is rich in pigments and blood vessels, including iris, ciliary body and choroid.
Iris: ring-shaped, located at the forefront of the uvea and in front of the lens, with radial wrinkles on the surface called texture and uneven depressions. People of different races have different iris colors. There is a 2.5-4mm round hole in the center, which is called the pupil.
The ciliary body is located in front of the iris root, behind the choroid, on the side of the sclera, and inside the equatorial part of the lens through the suspensory ligament.
The choroid lies between the sclera and retina. The blood circulation of choroid nourishes the outer layer of retina, and its rich pigment plays the role of shading darkroom.
The inner layer is the retina, a transparent membrane, which is the first stop of nerve information transmission formed by vision. It has a fine network structure and rich metabolic and physiological functions.
The end of the retinal visual axis is the fovea maculata. Macular area is the special area with the most acute vision on the retina, with a diameter of about 1-3mm and a small fovea in the center, that is, fovea. There is a reddish area with a diameter of 1.5mm, about 3mm, on the nasal side of the macula. This area is the optic disc, also called the optic papilla, which is the exit part of the retina and the place where the visual fibers converge and transmit to the visual center. There are no photoreceptor cells, so it appears as an inherent dark area in the field of vision, which is called physiological blind spot.
2. Intraocular cavity and contents
The eye includes anterior chamber, posterior chamber and vitreous cavity.
Ocular contents include aqueous humor, crystals and vitreous body. All three are transparent and are called refractive media together with cornea.
Aqueous humor is produced by ciliary process, which nourishes cornea, lens and vitreous body and maintains intraocular pressure.
Crystal is an elastic transparent body, shaped like a biconvex lens, located behind the iris and pupil and in front of the vitreous body.
Vitreous body is a transparent colloid, which fills the cavity behind 4/5 of eyeball. The main ingredient is water. Vitreous body has refractive effect and also supports retina.
3. Optic nerve and visual pathway
The optic nerve is a part of the central nervous system. Visual information obtained from retina is transmitted to brain through optic nerve.
Visual pathway refers to the whole nerve impulse transmission path from retina to cerebral visual cortex.
4. Eye accessories
Eye accessories include eyelid, conjunctiva, lacrimal apparatus, extraocular muscles and orbit.
Eyelids are divided into upper eyelids and lower eyelids, which live in front of the orbit and cover the front of the eyeball. The upper eyelid is bounded by eyebrows, and the lower eyelid is connected with facial skin. The gap between the upper and lower eyelids is called blepharoptosis. The joint of the two eyelids is called the inner canthus and the outer canthus respectively. The fleshy bulge in the inner canthus is called lacrimal caruncle. There is a perforated nipple on the inner side of the upper and lower eyelid margins, called lacrimal punctum, which is the opening of lacrimal canaliculus. Physiological function: the main function is to protect the eyeball. Because of frequent blinking, tears can wet the surface of eyeball, keep corneal luster and clean dust and bacteria in conjunctival sac.
Conjunctiva is a thin and transparent mucous membrane covering the back of eyelid and the front of eyeball. According to anatomical position, it can be divided into three parts: eyelid conjunctiva, bulbar conjunctiva and fornix conjunctiva. The saccular space formed by conjunctiva is called conjunctival sac.
Lacrimal gland organs include lacrimal gland and lacrimal duct that secrete tears.
There are six extra-ocular muscles that control the movement of the eyes. The four rectus muscles are: upper rectus, lower rectus, inner rectus and outer rectus. The two oblique muscles are the superior oblique muscle and the inferior oblique muscle.
The orbit consists of seven skulls: frontal bone, sphenoid bone, ethmoid bone, palatal bone, lacrimal bone, maxilla and zygomatic bone. It is a quadrangular cone-shaped nest inclined slightly inward and upward, with its mouth facing forward and its tip facing backward, and has four walls: upper, lower, inner and outer. Adult orbital depth is 4~5cm. Except the eyeball, extraocular muscles, blood vessels, nerves, lacrimal glands and fascia, the tissues in the orbit are full of fat, which plays a buffering role.
Computers do great harm to eyesight, so people who often operate computers should eat more eye-catching foods, such as medlar, chrysanthemum and cassia seed. Drinking chrysanthemum tea often can also get the effect of clearing heart and improving eyesight. Lycium barbarum clearing liver and improving eyesight is also of great benefit to protecting eyesight. Drinking tea can prevent vision loss and restore vision. It is generally believed that drinking tea has anti-radiation effect and can reduce the radiation harm of X-rays to computer screens. Tea is rich in tea polyphenols (50%) and lipopolysaccharide, which can adsorb and capture radioactive substances, and then be excluded from the body by combining with them.
Lack of essential fatty acids, vitamins A, K, E and B can reduce the body's tolerance to radiation and provide them properly in the diet. Such as milk, eggs, liver, cauliflower, cabbage, eggplant, lentils, carrots, cucumbers, tomatoes, bananas, apples and so on. Scientists in China found that Chinese cabbage and radish can resist radiation. Cruciferous vegetables such as rape, green vegetables, mustard greens, Chinese cabbage and radish are not only common delicious dishes on people's tables, but also have the function of preventing radiation damage.
Let me talk specifically about which foods can protect against radiation:
1, a food rich in collagen elastic substances. Representatives of this kind are kelp, laver, sea cucumber, animal skin, bone marrow and so on. Because collagen in food has adhesion, it can adhere to radioactive substances in the body and excrete them, and elastic substances contained in animal skin also have the function of repairing damaged skin.
2. Foods rich in antioxidant active substances. Cruciferous vegetables such as rape, green vegetables, mustard greens, Chinese cabbage and radish are not only common delicious dishes on people's tables, but also have the function of preventing radiation damage. Fresh vegetables are "cleaners" in the human body. The secret is that vegetables have a "secret weapon"-alkaline components, which can make blood alkaline, dissolve toxins deposited in cells and excrete them with urine.
3. Food with detoxification function. Such as pig blood, black fungus, etc. Pig blood is rich in plasma protein. After being decomposed by digestive enzymes, plasma proteins can react with dust and harmful radioactive metal particles entering the human body, become insoluble new substances, and then be excreted. The biggest advantage of auricularia auricula is that it can help excrete cellulose, making it difficult for these harmful fibers to stand in the body. This kind of food can help us expel harmful substances from our bodies, leaving no room for radioactive substances.
4, eyesight food. This kind of food is mainly aimed at urban white-collar workers, students and other people who have been facing computer work for a long time. Computers do great harm to eyesight, so people who often operate computers should eat more eye-catching foods, such as medlar, chrysanthemum and cassia seed. Drinking chrysanthemum tea often can also get the effect of clearing heart and improving eyesight. Lycium barbarum clearing liver and improving eyesight is also of great benefit to protecting eyesight. Drinking tea can prevent vision loss and restore vision. It is generally believed that drinking tea has anti-radiation effect and can reduce the radiation harm of X-rays to computer screens. Tea is rich in tea polyphenols (50%) and lipopolysaccharide, which can adsorb and capture radioactive substances, and then be excluded from the body by combining with them.
5. Maintain the balance of nutrition in the body. Studies have shown that the lack of essential fatty acids, vitamins A, K, E and B can reduce the human body's tolerance to radiation and provide them properly in the diet. Only adding any 1 vitamin can not obtain the expected nutritional effect. The nutritional balance of minerals is particularly important. The plasma concentrations of potassium, sodium, calcium and magnesium in the body must be appropriate, otherwise the water-electrolyte balance cannot be maintained, which may be harmful to health and even life-threatening. The relationship between trace elements and other nutrients is also very important. Zinc has an important influence on the digestion, absorption and metabolism of many nutrients, including protein and vitamins. When we are injured by radiation, too many or unbalanced minerals, including trace elements, will have adverse effects. This nutrition can be supplemented by milk, eggs, liver, cauliflower, cabbage, eggplant, lentils, carrots, cucumbers, tomatoes, bananas, apples and other foods.
Eyes should also be moisturized.
On the surface of our eyeball, there is a layer of tear film with lubricating function, which is constantly refreshed with the blink of an eye to keep the eyes moist. If the air is always dry or absorbed, after about 10 seconds, dry spots will appear on the tear film and the surface of the eyeball will become drier and drier. So in general, blink 10-20 times per minute. When you concentrate on reading or operating the computer, the blink frequency will be significantly reduced to about 5 times per minute. Because the eyeball is dry, the eye between cornea and eyelid is easy to bruise when it is closed, which leads to dryness, fatigue, discomfort, inflammation and pain, and forms dry eye syndrome. If you don't pay attention to it, corneal ulcers and scars may appear, which will eventually lead to decreased vision.
From this point of view, paying attention to eye care and improving the quality of life should become a topic that people can't underestimate. But for people who are keen on surfing the internet or watching TV, it is a bit reluctant to alleviate the phenomenon of staring. So, can we develop an artificial tear to protect our eyes? American scientists have made useful explorations on this. They developed a disinfectant eye drop called "Tears Ran" to imitate natural tears. It has the properties of natural tears, can be combined with tears, has a mild effect, can quickly and continuously relieve dry eyes, allergies and irritation symptoms, and can replace tear film to eliminate eyeball burning, fatigue and discomfort.