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The effects of excessive usage of computer
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Eyesight
Vision is the learned ability to see for information and performance; it allows us to understand things that we cannot touch, taste, smell or hear. 20/20 vision does not mean perfect eyesight. 20/20 vision simply means that at a 20 ft. distance a person is able to see a certain letter than an average eye should be able to see at that distance. You can have 20/20 vision and lack the abilities to use your two eyes together as a team, to judge distances, to identify colors and to coordinate your eyes with hand and body movements. About four in ten people have "perfect" vision.
There are also various eye disorders associated with eyesight such as astigmatism, farsightedness, and nearsightedness. Astigmatism is a condition in which vision at all distances may be blurred or distorted. An irregularly shaped cornea, causing light images to focus on two separate points in the eye, characterizes this condition. When the front of the eye is more oval than round, light does not focus properly on the back of the eye, also known as the retina. Astigmatism is not a disease, but is actually a vision condition that is quite common--only moderate to highly astigmatic eyes need corrective lenses. The signs and symptoms of severe astigmatism are blurred or distorted vision. For mild astigmatism the symptoms are headaches, eyestrain, fatigue, and blurred vision at certain angles. The causes of astigmatism are unclear. It may be genetically inherited or may result from various environmental factors such as poor lighting, incorrect posture, or an increased use of the eyes for close work.
Another eye disorder is farsightedness, also known as hyperopia. With this disorder, objects are seen clearly far away but are blurry close up. The eyeball is too short for the lens to focus a clear image on the retina. More than half of all people who wear glasses are farsighted. The signs and symptoms of farsightedness are aching or burning eyes, suffering from eyestrain, general tension, fatigue or headaches after close work, becoming irritable or nervous after prolonged concentration, and difficulty concentrating and maintaining a clear focus on near objects.
Nearsightedness also known as myopia, is a disorder where one can see clearly close up, but see blurry at a distance (for example, not being able to read the blackboard but being able to read a book). This occurs when the eyeball is too long or the cornea is too curved to focus on the retina.
McGuire, C. (2011, April). Workplace Safety 100 Years Ago. Safety Compliance Letter(2524), 1-6. Retrieved April 22, 2014, from http://search.ebscohost.com/login.aspx?direct=true&db=bth&AN=60166397&site=ehost-live&scope=site
Glaucoma, one of the leading causes of blindness, is estimated to affect 1 of every 50 adults. Although glaucoma can occur at any age, the risk of developing the disease increases dramatically after the age of 35. Glaucoma is also more likely to develop in patients who are severely nearsighted, have a family history of the condition, diabetics and Black or African American. This disease often goes unnoticed until permanent vision loss has occurred. Visual damage from glaucoma can be prevented by early diagnosis and careful treatment. Glaucoma is related to elevated fluid pressure of the eye which is causing loss of side vision. It is a series of diseases which damage the optic nerve. Damage to the optic nerve and retina causes blind spots in the field of vision. When the entire nerve is destroyed, blindness will occur. Glaucoma is usually caused by an increase in the fluid pressure in the eye. The front part of the eye contains a clear, nourishing fluid called aqueous which constantly circulates through the eye. Normally, this fluid leaves the eye through a drainage system and returns to the blood stream. Glaucoma occurs from an overproduction of fluid or when the drainage system becomes blocked, causing fluid pressure to increase. The high pressure causes damage to the optic nerve, resulting in permanent vision loss. The exact reason the fluid system in the eye stops functioning properly is not completely understood
Blindsight is often understood as supporting certain claims concerning the function and the status of the phenomenal qualities of visual perceptions. In this talk I am going to present a short argument to show that blindsight could not be understood as evidence for these claims. The reason is that blindsight cannot be adequately described as a special case of seeing. Consequently, it is not possible to draw inferences from it concerning the role of the phenomenal qualities for seeing.
What is marriage? For thousands years, marriage has been a combination between a man and a woman. When they love each other, they decide to live together. That is marriage. But what will love happen between two same sex persons? Will they marry? Is their marriage acceptable? It is the argument between two authors: William J. Bennett and Andrew Sullivan. The two authors come from different countries and have different opinion about same sex marriage. Sullivan agrees with the gay marriage because of human right, on the other hand, Bennett contradicts his idea because he believes that marriage should be between a man and a woman. Even though their theories are totally different, their opinions are very well established.
Processing capacity is a very broad and flexible category according to many researchers. In fact, the quote above mentioned suggests that we often fail to notice things that happen just in front of us (unexpected events that are often salient) either because we were completely absorbed by something else or because we had so many things to do at the same time that we couldn’t pay attention to it. We have all at least once failed to see a friend who was waving at us while eating in the cafeteria or walking in a crowded street. The primary question that we should ask ourselves is: how many things can we attend at the same time? The truth is that we didn’t perceive this friend because of a phenomenon called “inattentional blindness”. The problem is that the richness of our visual experience leads us to believe that our visual representation will include and preserve the same amount of detail (Levin et al 2000). In this paper we’ll see the different theories of inattentional blindness, and the classical theories demonstrating this paradigm.
As humans age, they frequently develop a condition known as presbyopia. This condition decreases the person's ability to focus sharply on those object which are nearby and is the result of the lens of the eye hardening. In addition, astigmatism requires a person wear prescription eyeglasses and/or contact lenses. Astigmatism arises when the curvature of the eye is irregular. The eye is normally shaped liked a soccer ball or basketball. With astigmatism, it takes on a more oval shape and resembles a football. Due to the irregular curvature, the eye processes light differently and leads to blurred vision. The degree of blurriness is determined by the degree of
This is a representation of the eye's lens system. This eye has no eye condition, such as nearsightedness or farsightedness, and the lens is drawn in its relaxed position. The light rays are focused appropriately on the retina. The thickness of the cornea is 0.449 mm, the distance from the cornea to the lens is 2.
Amblyopia is a condition in which visual acuity in one eye is greatly reduced. It is caused by lack of stimulation or disuse during visual development (Rose, 1998). Because the eye is not fully developed at birth (Jarvis, 1992, as cited in Rose, 1998), infants need stimulation to complete the visual neural pathway. When one or both eyes are inhibited, for example due to misalignment of one eye (strabismus) or a large difference in refractive power between two eyes (anisometropia), the neural pathway for the inhibited eye develops abnormally, or does not develop at all. At approximately six years of age eye development is complete (Stager, 1990, as cited in Rose, 1998). Before visual development is complete amblyopia can be treated. If it is caught and treated at an early age, normal vision can be preserved (Rose, 1998).
It is saddening to see humans of the female gender, who find themselves in a situation that requires introducing a new life into the world; to abort such a precious gift. Many may wonder how these poor, innocent, unborn children are then discarded after the abortion procedure. One cannot fathom the reason of these gruesome murders that happens within these medical facilities. Babies are disposed in the red waste bins of these facilities, and later incinerated. Some may either be flushed down garbage disposals or even be sold off for research purposes. The issue of abortion is not just a social one, but also a human rights issue among the unborn children. I believe if the human rights of these children has been violated, then all other rights of humans are certainly meaningless.
Open-angle glaucoma - With this form of glaucoma, the loss of vision occurs so gradually it is rarely noticed. However, as eye damage increases, you will eventually find that you have lost a lot of areas of your peripheral vision, especially the field of vision near your nose. As larger areas of your peripheral vision fade, you may develop tunnel vision -- vision that has narrowed so you see only what is directly in front of you. If glaucoma is not treated, even this narrowed vision disappears into blindness. Once gone, areas of lost vision canno...
Each one of us lives in our own unique world of perception. As individuals, we may experience life in an entirely different way through our senses and life experiences. Therefore, perception can be tricky since it is very personal to each one of us. According to the Merriam-Webster online dictionary, perception has three meanings; (1) “the way you think about or understand someone or something,” (2) “the ability to understand or notice something easily,” and, (3) “the way that you notice or understand something using one of your senses” (2014, para. 1). C.S. Lewis said, “What you see and what you hear depends a great deal on where you are standing. It also depends on what sort of person you are” (n.d., para. 11). In other words,
The accuracy and reliability of criminal statistics is something that has been of great discussion through criminology for decades. Whilst some believe that crime statistics are a misuse of time and resources, others believe that there is some use for them within the criminological community. The inaccuracies of criminal statistics are highlighted in abundance within academic articles and research, many of which highlight the main source as the dark figure of crime. Many also suggest other inconsistencies within official statistics to be influenced by law enforcement agencies and society. But whilst there is much research to suggest that criminal statistics are unreliable and of no use, there are some that suggest that this may not be entirely
One of the biggest challenges managers face in motivating employees is the ability to meet their safety needs. Because of the weak economy and high
The images formed on the two retinas are so unlike that they cannot be blended in the brain. Thus, a double image is perceived. The condition is known as diplopia, or double vision. Prismatic lenses are prescribed to correct this defect.Imperfections in the cones of the retina, resulting from heredity or disease, cause defective color vision. This is known as color blindness, or Daltonism. In total color blindness, everything appears in shades of gray.