The eye is an important sense for humans. Due to the eyes, we can look around. So that we can know the circumstances around us. If our eyes have problems, then we would feel uncomfortable. There are many other things we need to know about the senses that respond to light stimuli. For more details on how the eye will be discussed in the discussion of this paper.
A.Formulation of the problem :
1. What the eye?
2. How the eye works?
3. How do we keep our eyes?
4. Any disease that strikes the eye?
B. Eyes and The Sense
Understanding Currency
is the organ of vision that detect light. Who performed the simplest eyes that nothing else but to know whether the surroundings are light or dark. More complex eye is used to provide a visual understanding. The human eye has an automatic perfect way of working, the eye is formed by 40 different main elements and all of these parts has an important function in the process of seeing the damage or the absence of a functioning part of it will make impossible the eye can see. Translucent layer on the front of the eye is the cornea, iris are right behind him, in addition to members of the colors on the eyes. Iris can also resize automatically according to the power of the incoming light, with the help of muscles attached to it. For example when it is in a dark place slices will be enlarged to include as much light as possible. When the light power increases, the iris will shrink to reduce the light entering the eye.
Automatic setting system that works on the eyes as follows :
When the light into the eyes of nerve signals is formed and is sent to the brain, to give a message about the presence of light, and the light power. Then the brain sends back signals and ordered the extent to which the muscles around the iris must shrink. Other parts of the eye that works in conjunction with this structure is a lens. The lens focuses light duty entering the eye to the retina layer at the back of the eye. Because the muscles around the lens the light coming into the eye from different angles and different distances can always focused onto the retina. All the systems we have mentioned earlier are smaller, but far superior to mechanical equipment that is made to mimic the design of the eye by using the latest technology, artificial image recording system even the most modern in the world was still too modest if compared to the eye. If we contemplate all toil and thought has gone into making artificial image recording tool we will understand how much of superior technology creation eye. If we observe the portions are smaller than the cells of an eye, the wonder of creation is increasingly revealed.
Suppose we are looking at the crystal bowl filled with fruit,the light coming from this bowl to our eye penetrates the cornea and iris then focused on the retina by the lens so what happens on the retina, so that retinal cells can sense the presence of light when light particles called photons on retinal cells. When they produce an effect like a row of dominoes chain arranged in neat rows. First domino in retinal cells is a molecule called 11-cis retinal. When a photon about it this molecule changes shape and then push the changes to other proteins that bind strongly with the rhodopsin. Rhodopsin has now turned into a form that enables it to bind to another protein that is transducin. This transducin already exist in the cell but can not join because of incompatibilities form rhodopsin. This unification was followed combined one another molecule called GTP. Now the two protein rhodopsin and transducin and 1 chemical. And indeed the process has just begun a compound called GDP now has a form suitable for binding of another protein called phosphodiesterase that already exist in the cell. After the resulting molecule binds to form a mechanism that will move would begin a series of chemical reactions in cells. This mechanism produces reactions of ions in the cell and generate energy electrical energy stimulates the nerves that lie just behind the retina cells. Thus the shadow when the eyes of intangibles such as photons of light to continue his journey in the form of electrical signals. This signal contains visual information objects outside the eye. So that the eyes can see the electrical signals generated in the retina must be forwarded in the vision center in the brain. But the nerve cells do not relate directly to each other because there is a small gap that separates their connection points, then how this electrical signal to continue his journey here. A series of complicated mechanisms occurs, the electrical energy is converted into chemical energy without any loss of information that is being taken and in this way information is passed from one nerve cell to nerve cell next. Chemical molecule carrier is located at the connection point of nerve cells managed to bring the information coming from the eye from one nerve to another nerve. When moved to the next nerve signal is converted back into electrical signals and continue his journey to the other connection point, in this way the signals reached the visual center of the brain. Here the signal is comparing the information in the memory center and the shadow. and interpreted that finally we can see the bowl full of fruit, as we saw earlier. It was because of the perfect system consisting of hundreds of small component of this and all of this amazing series of events that occur in less than 1 second.
The parts in the eye
Beyond Organs
√ Eyelashes
Eyelashes, or rather hair eyes, is part of the eyelid that form strands of hairs. These hairs serve to protect that dust, sweat or water dripping from the forehead does not enter the eye. Eye hair is very soft hair. Tools for curl and thicken eyelashes mascara called.
√ Eyebrows
Serves as a protective eyebrows sensitive eyes from droplets of sweat that fell from the forehead, rainwater, or excessive sunlight. Shape eyebrows in humans is usually like a crescent with a rather sharp bends in the temples. Not infrequently also found people with the eyebrows of the left and right parts are concatenated into one. The shape of the eyebrows and the direction the hair grows on eyebrows intended to sweat or water can flow to the forehead and fell to the cheek, or towards the cheek over the top of the nose. Bone forms the forehead on the eyebrows also protects the eyes from sweat and water. Eyebrows also serves as retaining various kinds of dirt that can enter the eye, such as sand, dust and dandruff. Besides the hair on the eyebrows also increase the sensitivity of the skin to feel a foreign object near the eye, for example insects coming into the eye. In human communication, the eyebrows is one tool to reveal various expressions, such as amazement, angry, confused, or do not understand.
√ Eyelid
Eyelid is soft folds of skin that cover and protect the eyes. Some diseases related to inter alia the eyelid or eyelid ptosis dependent, which in most cases happens when the levator palpebrae muscles are not strong enough to hold the eyelid. Handling of pathological conditions this can be done by surgery using local anesthesia, and the state of the eye can be improved after surgery.
Organs Eyes Inside
The sections on cooperation eye organ deliver light from the source to the brain to be digested by the human nervous system.
These parts are :
- Cornea
Is the outermost part of the eye that receives light from the light source.
- Sclera
Is part of the eye wall white. The average thickness of 1 millimeter but in irensi muscles, thickened to 3 millimeters.
- The pupil and Iris
Of the cornea, the light will be forwarded to the pupil. The pupil determines the amount of light entering the eye deeper. Pupils will be widened if a dark room conditions, and will be narrowed if the bright room condition. The width of the pupil is affected by the surrounding iris. Iris serves as the diaphragm. Iris This is seen as the colored part of the eye.
- Eye Lens
Lens of the eye receives light from the pupil and pass them on to the retina. The function of the eye lens is set to focus the light, so the light falling directly on the retina yellow spots. To view a distant object (light coming from far away), the eye lens to be thinned. As for seeing objects that are close (light coming from close), the eyepiece will thicken.
- Retina
The retina is the most sensitive part of the eye to light, particularly the part of the retina called the yellow spots. After the retina, the light transmitted to the optic nerve.
- Optic Nerve
The optic nerve is the nerve that enters the ropes and cone cells in the retina, to get to the brain.
C. Various Eye Diseases
Sore eyes is the disruption of the function of the eye as a means senses that usually occurs in the physical part of the eye and the inside of the eye. Almost everyone could not avoid the pain, because the eye is one of the senses which is very open and become the most vital part in human organs, where the eye is a sensory tool that continuously used. Many people are looking for ways to treat diseases of the eye, but not many people know what exactly causes sore eyes.
Causes of eye pain can be categorized into two, namely :
1. Surface Sore Eyes
Pain in the surface of the eye is a condition where the pain comes from outside the structure of the eye's surface, some of the causes is :
~ Conjunctivitis
Conjunctivitis is one of the most common eye problem. Conjunctivitis is usually caused by allergies, bacteria, chemical, or viral inflammation of the conjunctiva (the membrane lining the eyelids soft and covering the eyeball).
The characteristics of eye pain caused by conjunctivitis is; eyes change color to pink. Usually mild pain or no pain at all / itchy redness.
~ Corneal Abrasions
Corneal abrasions are also a common cause of sore eyes. The cornea is one of the most transparent part of the eye, sensitive and gentle. Blisters usually occurs because of scratches to the surface of the cornea, such as from a foreign body or overuse of contact lenses.
~ Effects of Chemical and Burnsh
Effects of Chemical and burns a significant cause of the sore eyes. Chemical effect is in the form of acid or alkaline substances, such as household cleaners or bleach. The burns are usually derived from strong light sources, such as welding spark or flame also comes from the sun and lighting tools which have fairly high light intensity.
~ Blepharitis
Blepharitis usually occurs due to plugged oil glands at the edge of the eyelid.
~ Eye Irritation
Eye irritation characterized by small bumps on the eye, eye bumps is formed by the oil glands of the eye that is not normal. causing irritation to the eyes, even the pain is quite painful.
2. Pain in the Orbit of the Eye ( Orbital )
Orbital pain is described as pain that is contained inside the eye or behind the surface of the eye. Here are some of the causes of eye pain originating from the orbital :
~ Glaucoma
Glaucoma causes orbital pain, although most cases of glaucoma are not painful. Glaucoma is caused by increased intraocular pressure, or the internal pressure of the eye, which eventually can lead to defects in vision and even blindness if not treated. Intraocular pressure may increase due to blockage of the eye fluid or increased production of aqueous humor (the fluid that bathes the eye). This usually occurs in older people.
~ Iritis ( inflammation of the iris )
Iritis is an inflammation of the iris, or the colored part of the eye, causing pain in the eye.
~ Optic Neuritis
Neuritis Optic neuritis is an inflammation of the optic nerve. The optic nerve connects to the back of the eye. The cause of inflammation is usually derived from multiple sclerosis, viral infections or bacterial infections.
~ Sinusitis
Sinusitis, which is a bacterial or viral infection of the sinuses, can cause pain or orbital eye socket. Migrants, is a very common cause eye orbital pain associated with headaches.
~ Trauma Events
Trauma events, such as penetrating injury to the eye, eye blow with a foreign object, and motor vehicle collisions, which cause significant eye pain and injury. Scratches to the cornea usually associated with traumatic events that are painful. It is a common eye problems that cause people to seek medical help.
Diseases of the eyes is very diverse kinds, there is a sufficient treatment using medications and eye drops. There also has to go through surgery. The following is a common disease of the eye suffered by humans.
1. Cataract
Cataract is an eye disease that is characterized by the presence of fog on the lens of the eye. Normally transparent lens of the eye contains a lot of water, so that light can pass through easily. Although the new cells in the lens will always be formed, many factors can cause the area in the lens becomes opaque, hard, and solid. The lens is not clear will not be able to pass on the light to the retina to be processed and sent through the optic nerve to the brain. Cataract disease prevalent in tropical countries. This is related to factors associated with cataracts, the ultraviolet rays coming from the sun. Other causes are malnutrition which can accelerate the process of developing cataracts.
Causes Cataract
Most cataracts occur due to degenerative processes or age someone. Cataracts mostly appear in the elderly. Statistics show that more than 90% of people aged over 65 years suffer from cataracts. Approximately 55% of people aged 75- 85 years diminished eyesight due to cataracts. Although it can actually be treated, cataract is the leading cause of blindness in the world. Unfortunately, A cataract patients may not realize have undergone cataract disorder. Cataracts occur slowly-slowly so that people with impaired eyesight gradually. Because cataracts generally grow very slowly and does not affect the power of vision from the beginning. The new power of vision is affected after cataracts develop about 3-5 years. Therefore, cataract patients are usually aware of the disease after entering a critical stage. At the beginning of the attack, cataract patients feel ;
— Itching of the eye
— Tears easily come out
— At night sight impaired
— could not withstand the glare of sunlight or lamps
— The patient will see the membrane like a cloud in front of eyesight.
Cloud covering the lens of the eye is finally getting closer and cover all parts of the eye. When the cataract patients have reached this stage, the patient will lose his sight.
Generally, there are four types of cataracts as follows :
~ Congenital
Congenital, a cataract that occurred since the baby was born and developed in the first year of his life. This type of cataract is very rare.
~ Traumatic, is a cataract that occurs because of an accident on the eyes.
~ Secondary
Secondary cataracts are caused by the consumption of drugs such as prednisone and corticosteroids, as well as diabetics. Cataracts are 10 times more common suffered by people with diabetes than the general population.
~ Age_Related Cataracts, the most common type of cataract.
( Based on the location, there are 3 types of cataracth, namely nuclear sclerosis, cortical and posterior subcapsular );
Nuclear sclerosis is a lens changes gradually so that it becomes hard and yellowish. The views are much more affected than near vision (sight reading), even sight read can be better. Sufferers also have difficulty distinguishing colors, especially blue.
The type of cortical cataract occurs when the fibers of the lens becomes cloudy, it can cause glare, especially when driving at night.
Posterior subcapsular the occurrence of turbidity in the rear side of the lens. This Cataracts cause glare, blurry vision in bright light conditions, as well as the outlook declined read.
Common Symptoms of Cataracts Include :
— Vision is not clear, as there is a fog blocking objects.
— Sensitive to light.
— Can see the double in one eye.
— Require bright lighting to be read.
— Eyepiece turned into opaque like milk glass.
Cataracts can also occur in babies because the mother is infected with the virus during early pregnancy.
Other causes of Cataracts include ;
— Heredity
— Congenital defects
— Health problems
— The use of certain medications, especially steroids
— Unprotected eyes exposed to the sun in a long time
— Previous eye surgery
— Trauma (accidents) in the eye.
Medical Treatment
Solutions to cure medically cataract surgery is generally the way. Layer in the eye is removed and replaced artificial lens (intraocular lens). This operation is quite risky and does not promise a cure 100%. Recently discovered advanced technology, which is operating with a laser beam. All the way this treatment is highly dependent on the economic capacity of the patient, because of eye surgery requires a lot of fund.
2. Pterygium
Pterygium is an eye disease that is characterized by the growth of meat in the cornea of the eye. The meat is the conjunctiva ( the membrane that surrounds the white part of the eye ) meat that grow abnormally into the cornea. Pterygium can be small or can also grow larger and interfere with vision. Exposure to sunlight for a long time, especially UV rays, and chronic eye irritation by dust and drought is strongly suspected as the main cause of pterygium.
Pterygium symptoms are red eyes, irritation, inflammation, and blurred vision. Although someone who felt the symptoms are not necessarily exposed to pterygium, but recommended to remain see the eye doctor. Appears as a protrusion of white tissue with blood vessels in the inner edge or outer edge of the cornea. Pterygium can cause deformation of the cornea resulting in astigmata and other vision disorders. If it gets into the area of the pupil and interfere with vision, pterygium should be removed surgically. To prevent the recurrence of pterygium, field workers should use protective glasses or hats.
Pterygium Medical Treatment
For pterygium, medical treatment is generally performed by using eye drops or oral medication containing anti-inflammatory. However, if the pterygium is large enough and very disturbing vision, surgery can be performed.
3. Glaucoma
Glaucoma is an eye disorder that is characterized by damage to the optic nerve that serves to bring the message of light from the eye to the brain. Optic nerve damage is caused by excess fluid in the humor that fills the eyeball. Eye fluid produced by tissues in the front of the eyeball is actually serves to bring food to the cornea and lens of the eye. Excess fluid in the eyeball may occur due to production that is too much or the rate of spending into the bloodstream too little. When it began to accumulate in large quantities, causing eye fluid pressure growing on all parts of the eye including the optic nerve. The pressure will eventually suppress the cells in the retina and optic nerve crush. As a result, the optic nerve is no longer able to carry his message to the brain that result in one's vision to be reduced. If not promptly treated, the person can suffer blindness. There are more than 20 kinds of glaucoma which has similar developments.
The forms of glaucoma are grouped into two major groups as follows :
A. Open Angle Glaucoma
Open-angle glaucoma is a progressive disease, meaning that will worsen if not treated , means it will worsen if not treated. Initially there are only a few nerve cells are damaged. The points blindness will develop in the area of the nerve cells are located. The longer, the more nerve cells will be damaged and the greater area of vision is lost. Finally, one can experience total blindness. Generally no early symptoms, which means the open-angle glaucoma. Vision loss occurs very slowly, often lasting several years. If only one eye is affected, the other eye will take over the function of vision. Therefore, most people with glaucoma are unaware that his eyesight has declined. Someone new will be aware of the glaucoma after severely diminished eyesight.
B. Angle Closure Glaucoma
Closed-angle glaucoma occurs very quickly. Some kind of accident or changes in the eye can cause eye fluid develops suddenly. The effects of this type of glaucoma will appear in a very short time.
Glaucoma Medical Treatment
Medically glaucoma can be overcome either by medication or surgery. Generally, prior to surgery, will be tried first drug use. Medications used to treat glaucoma are drugs that can reduce intraocular pressure. In general, the drug works to reduce the rate of production of eye fluid or increase the pace of expenditure. However, all the conventional drug has considerable side effects such as dangerous allergic reactions, blurred vision, headaches, eye inflammation, decreased blood pressure, decreased heart rate, and the incidence of kidney stones.
Alternative
√ As an alternative glaucoma can be treated with vitamins and minerals that can lower intraocular pressure , such as vitamin C, B1 (thiamin), chromium, and zinc.
4. Minus Eye (myopia)
Myopia is often called myopic is the kind of eye disorders that cause the sufferer can not see the object of Remote well. Myopia is often accompanied by disturbances of cylindrical eye (astigmatism). This disorder arises from within or taken from someone's childhood. Myopia is common worldwide. In developed countries, the percentage of people who suffer from myopia usually tow.
Minus mild eye can generally be corrected by using glasses or contact lenses.
But to the eye with high minus, use glasses often cause disturbed patient activity, because the glasses are used must have a thick lens. If it is so, refractive surgery is needed to overcome. When treated with eye drops before puberty, these disorders can be cured. But if treatment is done after puberty, generally only be derived approximately 75%, although in some cases there can be completely cured.
Myopia Medical Treatment
Generally, eye minus, plus eye, and astigmatism can be overcome with the use of glasses and contact lenses. Refractive surgery can also be performed, especially for patients who have severe.For patients who have severe, it takes a very thick glasses that are less practical and can interfere with daily activities. Glasses and contact lenses is a tool that is commonly used to treat eye minus, plus eye, and cylindrical.
5. Eye Plus (hypermetropia)
Hypermetropia is a type of eye disorders that cause the sufferer can be seen from a distance better than from close range. Similarly, the so-called plus eyes, nearsightedness, and hyperopia.
Eye Plus Medical Treatment
Generally, eye minus, plus eye, and astigmatism can be overcome with the use of glasses and contact lenses. Refractive surgery can also be performed, especially for patients who have severe. For patients who have severe, it takes a very thick glasses that are less practical and can interfere with daily activities.
6. Astigmatism (cylindrical)
Astigmatism is an irregularity arches refractive surface of the eye resulting light beam is not focused at one point on the retina eye. There are two types of astigmatism, the cornea astigmatism caused by arcing irregularity or refractive power of the cornea and lens astigmatism refractive power due to the irregularity of the eye lens. Astigmatism causes sufferers have difficulty seeing things clearly or become blurred, especially for objects that are small. Astigmatism are generally suffered by people with myopia can usually be corrected with glasses or contact lenses cylindrical lens. Can also be performed refractive surgery.
Astigmatism Medical Treatment
Generally, eye minus, plus eye, and astigmatism can be overcome with the use of glasses and contact lenses. Refractive surgery can also be performed, especially for patients who have severe. For patients who have severe, it takes a very thick glasses that are less practical and can interfere with daily activities.
D. Habits that Damage the Eye
Destructive habits of the most common eye is staring at a computer screen for too long. It was not the only thing that bothered eye health. If allowed, not only eye sore but also there is a serious problem. How to maintain healthy eyes naturally is actually easy to prevent bad habits. Inflammation of the eyes can result from such things as too long staring at a computer screen high stress.
Habits that Damage the Eye :
~ Read while sleeping.
From now on your eye care by not reading in a state of sleep position. Reading in this position can make the eyes tense. Not only could make it difficult to focus the eyes but also a headache.
~ Too long at the computer.
Beware those who work long hours in front of a computer screen. Occasionally getting up from your seat and walk around or stare at the trees for a moment. The computer screen can make dry eye that required glasses to withstand light.
~ Watching television
Such as computer screens, television screens also damage. Eye damage as a result of this can happen quickly. Keep looking at the distance to a television screen so that your eyes stay safe.
~ Reading on the way.
Reading has become a hobby some people while on a trip in the car or train. But this should be avoided because the movement of the vehicle can make the eye muscles to work extra adjusting the constant movement.
~ Excessive exposure to light
You've squinting due to the scorching sun. It can harm the eyes so use sunglasses when outdoors.
~ The use of soft contact lenses.
Soft lens wear is fine if we did not want to be bothered with the use of glasses. Everyone would prefer a practical but as we know it requires the use of soft lens care more. Mishandled in the sense that less can keep it clean will affect eye irritation and makes the red eye. Of course, if allowed to drag on will be able to damage the eye.
~ Rubbed his eyes.
Usually done when rubbed his eyes itchy due to a foreign object into the eyeball. Habit rubbed his eyes will only worsen the situation. Rubbed his eyes because of the likely foreign objects entering the eye was going to scratch the surface of the cornea of the eye. If rubbed too hard it can also cause rupture of small vessels in the eye so that blood circulation becomes smooth.
E. Color Blindness
Color Blindness is a disorder caused by the inability of cone cells of the eye to capture a certain color spectrum caused by genetic factors. Color blindness is a genetic disorder that is passed down from parents to their children, this disorder often also called sex linked, because this disorder is carried by the X chromosome. That is the Y chromosome does not carry color blind factor. This is what distinguishes between people with color blindness in men and women. a Woman contained the term 'hereditary', it shows there is one X chromosome that carries the nature of color blindness. Women with hereditary, not physically abnormal color blind as normal women in general, but women with hereditary factors potentially reduce color blind to his future. If the second X chromosome contains a color-blind factor then a woman is suffering from color blindness. Nerve cells in the retina consists of stem cells which are sensitive to black and white, as well as cone cells are sensitive to other colors. Color blindness occurs when light receptors in the retina nerve changes, especially cones. Color blindness itself can be classified into three types, namely trichomoniasis, dikromasi, and monochromatic :
1.Trichomoniasis.
Color blindness is the type trichomoniasis change the color sensitivity of one or more types of cone cells. Type of color blindness is most commonly experienced than other types of color blindness.There are three kinds, namely trichomoniasis :
~ Protanomali ( which is a weakness in red ).
~ Deuteromali ( green color weakness ).
~ Tritanomali ( weaknesses in blue ).
2.Dikromasi
Dikromasi is the absence of one of three types of cone cells, which consist of :
~ Protanopia namely the absence of a red cone cells so that the brightness of the red color and the combination of reduced.
~ Deuteranopia namely the lack of cones sensitive to green.
~ Tritanopia namely the lack of cones sensitive to blue.
3.Monochromatic.
While monochromatic characterized by loss or reduction of all color vision, so that looks just white and black on the kind typical and a bit of color on what kind of atypical. This type of color blindness prevalence is very rare. Color blindness can be tested with Ishihara test that uses colored circles are made with a certain article that can only be seen or can not be seen by people with color blindness.
F. Conclusion
The eye is the organ of vision that detect light. Who performed the simplest eyes that nothing else but to know whether the surroundings are light or dark. More complex eye is used to provide a visual understanding. By maintaining eye health, then we have been grateful with what we have. Not only that, by maintaining the health of our eyes, the eyes will function as it should so it does not interfere with our activities.
G. Suggestion
Some of these tips may be in trying to maintain eye health, among others :N
√ Eat nutritious foods complete, it would be good for the eyes as well. in general, foods that are good for the eyes is that lots of vitamin A and carotene such as papaya, carrot, mango, and others.
√ Rest and sleep well
With enough rest and sleep, the eyes are also quite break.
√ Keep the intensity at the Computer & TV. Do not be imposed if the eye is completely exhausted. Even if I have to rest for a moment after the front of the computer for two hours. Arrange such features of the monitor so as not to make the eyes become tired quickly and safely to the eye ( use a monitory filter ).
√ Do not rubbed his eyes!!
Wear synthetic tears can help relieve itching because it can accelerate flushing foreign objects from the eye so that itching may soon disappear.
√ Read the ideal viewing distance and with adequate lighting.
√ Every now and then do the relaxation of the eye by making small massaging the muscles around the eyes with her eyes closed.
√ Perform routine eye examination, and immediately went to the doctor in case of matters which may disturb your eyes and cause to be harmful.
Thus the explanation of the human eye.
Hope it is useful. Thank you..
Sources : from various reliable sources which we summarize here.
: http://wwwhome.lorentz.leidenuniv.nl/~saarloos/Correlateds/rhodopsin.html
https://en.m.wikipedia.org/wiki/Conjunctivitis http://www.glaucoma.org/gleams/what-are-the-symptoms-of-glaucoma.php http://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/astigmatism?sso=y http://www.colourblindawareness.org/colour-blindness/ https://en.m.wikipedia.org/wiki/Ishihara_test http://genetics.thetech.org/ask/ask3hh
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