Night Blindness is a genetic disorder in which the sufferer has trouble seeing at night. Two things cause this disorder in general. The first cause is a lack of vitamin A which helps develop the retina and vision receptor cells. Vision receptor cells consist of cones and rods, cones for bright light and rods for less light. When there is a vitamin A deficiency, the rod cells don’t develop properly. The second cause is a genetic inheritance. Night blindness is a sex-linked disorder because the X-chromosome was found to be different than normal in people with the disorder.
There are many vision-related effects this disorder can have on a person. In most cases, the person isn’t completely blind in dark areas, but sees things a lot darker than they really are. In other cases, it takes the person’s eyes much longer than normal to adjust to different light settings. For example, if a person with night blindness suddenly has the lights turned off in front of them, it may be up to 10 minutes before they can see anything at all. Also, the same thing happens when going from dark to light. The sufferer will see extremely bright images when flooded with light after having adjusted their eyes to darkness.
There are many treatments for night blindness that exist today. The most common treatment is taking vitamin A supplements to restore the vitamin A that helps develop and maintain the retina. Also, zinc supplements can be taken as well to further strengthen the retina. Physical forms of treatment include lasers, freezing, injection of gas into the eye, scleral buckling, and removal of the gel inside the eye.
This disorder is usually accompanied by myopia (nearsighted). About half of teenagers with myopia will develop some form of night blindness. These cases start out around the age of fifteen. Also, about 52% of women said they had trouble seeing at night during their last pregnancy.
11 million people were killed during the holocaust, prison camps, prisoners were forced to do hard physical labor. Torture and death within concentration camps were common and frequent. In the documentary The Stanford Prison Experiment twenty-four male students out of seventy-five were selected to take on randomly assigned roles of prisoners and guards in a mock prison as an example of unexpected effects that can occur when phycological experiments into human nature are shown. The novel "Night" demonstrates as well how powerful a few people can be by Elie's experience of the Jews in the camps and the soldiers showed nothing resembling consideration for any of the people in the camps. Both the documentary and the novel convey the notion of mans inhumanity against man by the roles of each person and how unfairly of the
How can inhumanity be used to make one suffer? The book Night by Elie Wiesel is about a young Jewish boy named Elie who struggles to survive in Auschwitz, a concentration camp during the Holocaust. Throughout the memoir, there are many instances where inhumanity is portrayed. The theme seen in this novel is inhumanity through discrimination, fear, and survival.
There are all different types of medical and disable human beings out in this world. There are also different types of disabilities such as a physical or mental condition that limits a person 's movements, senses, or activities. I choose a sensory impairment, Diabetic Retinopathy which is one of the types of visual impairments that people may happen to get. You also have four other types of visual impairments, cataracts, glaucoma, retinitis pigmentosa, and retrolental fibroplasia that you can also get. Diabetic Retinopathy is a complication of diabetes that affect the eyes.
Throughout the novel there are several instances where characters, including the narrator, are physically blind or experience the loss of their sight. Such cases of physical blindness represent the unwillingness or incapability to see past the prejudices and falsities of an American society based on the superiority of Whites. An important example of this in the text is the boxing scene in which the narrator is fooled into fighting other fellow African Americans for the enjoyment of notable white folks in the community. The narrator is searching for truth behind the horror of this arranged fight, but his eyes are blindfolded by oppressive Caucasian hands:
According to Baily and Hall, while visual impairment early in life is associated with inherited congenital disorders, abnormal fetal devepment, and problems associated with premature birth, most eye conditions are associated with aging. They claim that over 70% of the visually impaired population in the United States is over 65. Age related maculopathy, also called macular degeneration, or AMD, impairs the center of vision in older individuals. The macula is the region in the back of the retina that surrounds and includes the fovea (Goldstein 1999). It is important to understand that when this degeneration progresses enough, the condition constitutes blindness because the foveal area is what is used to focus on something. Most cases do not progress this far, but between five and 20% do. Allikments and Shroyer claim that 11 million people in the United States alone suffer some degree of this impairment, with 75% of those individuals being 75 or older. Seven percent of this older age group reportedly suffer advanced forms. Freidman reports the disease as most common in developed countries.
Albinism is a genetically linked disease and is presented at birth; it is characterized as a lack of pigment called melanin that normally gives color to a person’s skin, hair and eyes. This results in milky white hair and skin, and blue- gray eyes. Melanin is synthesized from amino acid called tyrosine, which originates from the enzyme tyrosinase. Albinism affects all races and both sexes; people with this disease have inherited a recessive, nonfunctional tyrosinase allele from both parents (Saladin 189). The inheritance of Albinism is coded in the gene of the parent’s alleles. Alleles are two different versions of the same gene or trait and are found on the same place of a chromosome. One allele is coded for the production of melanin that will produce normal skin, hair and eye color and another allele that represent the lack of melanin that produces abnormal skin, hair and eyes.
It is a rare condition that affects 2 % of Americans. Signs of pathological myopia include: Bending or distortion of straight lines, altered color perception, reduced contrast sensitivity, and increasing gloss of central vision. It is a quick severe progression of myopia and loss of vision is the end result. There is an increased risk of retinal detachment and other degenerative changes in the back of the eye (bleeding from abnormal blood vessel growth). If any of these things occur the risk of cataracts could increase. Treatment calls for a combination of a drug and a laser procedure called photodynamic therapy. It is reported to be the seventh ranking cause of legal blindness in the United States of America the fourth ranking cause in Hong Kong and the second in parts of China and Japan this form of myopia frequently progresses in adult life, with small intermittent steps of elongation being observable at any age. The adult progression appears to be due to the stretching of the walls of the eye. Genetically weak elements of the scleral wall are prone to thinning and stretching. One of the major forces at work in this stretching process appears to be the normal intra-ocular pressure (Ward
As the story of the” Invisible Man” by Ralph Ellison continues, the reader is able to explicitly see his journey in college. Invisibility as well as blindness is evident in these stories. Through the use of metaphor and vivid details the author once again conveys his message of how invisibility is a major part in his life.
When defining the word blindness, it can be interpreted in various ways. Either it can be explained as sightless, or it can be carefully deciphered as having a more complex in-depth analysis. In the novel Blindness, Jose Saramago depicts and demonstrates how in an instant your right to see can be taken in an instant. However, in this novel, blindness is metaphorically related to ‘seeing’ the truth beyond our own bias opinions.
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).
ABSTRACT: The aim of this paper is to defend a broad concept of visual perception, according to which it is a sufficient condition for visual perception that subjects receive visual information in a way which enables them to give reliably correct answers about the objects presented to them. According to this view, blindsight, non-epistemic seeing, and conscious visual experience count as proper types of visual perception. This leads to two consequences concerning the role of the phenomenal qualities of visual experiences. First, phenomenal qualities are not necessary in order to see something, because in the case of blindsight, subjects can see objects without experiences phenomenal qualities. Second, they cannot be intentional properties, since they are not essential properties of visual experiences, and because the content of visual experiences cannot be constituted by contingent properties.
People with ocular albinism, which only the eye lacks melanin pigment, while everything else appears normal. People who have this have a variety of the eye disorders because of the lack of pigment impairs normal eye development. These effected are extremely sensitive to bright light. Treatment for ocular albinism includes the use of visual aids and surgery for strabismus.
Unfortunately, humans become colorblind at night because their eyes switch from normal daytime vision to a color-insensitive rod system. Unlike humans, a lot of other animals have the ability to see in the dark. This nocturnal ability is a major subject of research because scientists want to know what causes it, what methodology lies behind it, and what limitations there are.
Color Blindness means that you have trouble seeing the colors green, blue, or red or a mix of these colors. It is an abnormal condition characterized by the inability to clearly distinguish different colors of the spectrum. It is very rare that a person doesn’t see any color at all. Color Blindness is also called color vision problem. The difficulties can range from mild to severe. Color blindness is a misleading term because people that have it aren’t really totally blind. They tend to see colors in a limited range of hue. The scientific name for total color blindness is Monochromasy. Having color blindness would change a normal person’s life. It makes it harder to read and learn, and you may not be able to have certain careers. Although having color vision problems can affect your life greatly, you can still learn to make up for your problems seeing color. There are many other types of color vision problem. Deuteranomaly is a type that is considered green weak. Dichromasy is another type, which can be divided into Protanopia and Deuteranopia. People with this see no difference between red, orange, yellow, and green. Protanopia has much reduced color vision of the colors red, orange, and yellow. Deuteranopia is the same thing as Protanopia except without the abnormal dimming which makes it different. Last would be Tritanopia and Tritanomoly. Both of these types of color blindness are blue-green –color blindness with not many differences between them. In Tritanopia the s-cones are completely missing from the eye, and in Tritanomoly the s- cones have some kind of mutation.
Blindness does not mean that the child is totally without usable vision. Most of blind children have varying amounts of vision, which can be quite helpful. “Legal blindness” is a term you may hear. It means that a child has 10% or less of normal vision. Teachers need to know that many factors affect what, and how much, a child may see at any particular time. Type of eye condition, fatigue, lighting, excitement, etc. all affect a partially sighted child’s vision.