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What are the different types of blindness?

Color blindness is the inability to perceive differences in various shades of colors, particularly green and red, that others can distinguish. It is most often inherited (genetic) and affects about 8% of males and under 1% of women. People who are color blind usually have normal vision otherwise and can function well visually. This is actually not true blindness.

Night blindness is a difficulty in seeing under situations of decreased illumination. It can be genetic or acquired. The majority of people who have night vision difficulties function well under normal lighting conditions; this is not a state of sightlessness.

Snow blindness is loss of vision after exposure of the eyes to large amounts of ultraviolet light. Snow blindness is usually temporary and is due to swelling of cells of the corneal surface. Even in the most severe of cases of snow blindness, the individual is still able to see shapes and movement.

People often say, "I am 'blind as a bat' without my glasses." All bat species have eyes, and most have excellent vision. More importantly, the term blindness means the inability to see despite wearing glasses. Anyone who has access to glasses and sees well with the glasses cannot be termed blind.

The many causes of blindness differ according to the socioeconomic condition of the nation being studied. In developed nations, the leading causes of blindness include ocular complications of diabetes, macular degeneration, and traumatic injuries. In third-world nations where 90% of the world's visually impaired population lives, the principal causes are infections, cataracts, glaucoma, injury, and inability to obtain any glasses.

Infectious causes in underdeveloped areas of the world include trachoma, onchocerciasis (river blindness), and leprosy. The most common infectious cause of blindness in developed nations is herpes simplex.

Other causes of blindness include vitamin A deficiency, retinopathy of prematurity, blood vessel disease involving the retina or optic nerve including stroke, ocular inflammatory disease, retinitis pigmentosa, primary or secondary malignancies of the eye, congenital abnormalities, hereditary diseases of the eye, and chemical poisoning from toxic agents such as methanol.

Medically Reviewed by a Doctor on 2/25/2015

Blindness - Causes Question: Please discuss the cause of blindness in a relative or friend?

Blindness - Diagnosis Question: Discuss the events that led to a diagnosis of blindness.

Blindness - Treatment Question: Please discuss treatments for blindness received by you or someone you know.

Blindness - Legally Blind Question: Please discuss in what ways being "legally blind" has affected your lifestyle.

Medical Author:

Andrew A. Dahl, MD, is a board-certified ophthalmologist. Dr. Dahl's educational background includes a BA with Honors and Distinction from Wesleyan University, Middletown, CT, and an MD from Cornell University, where he was selected for Alpha Omega Alpha, the national medical honor society. He had an internal medical internship at the New York Hospital/Cornell Medical Center.

Medical Editor:

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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Blindness Symptoms, Causes, Treatment - MedicineNet

By Jose Saramago. Translated from the Portuguese by Giovanni Pontiero from the 1995 Ensaio sombre a Cegueira. 309 pages London: The Harvill Press, 1997 ISBN: 0-15-136700-9

Comments of Bob Corbett October 2001

How are we to imagine a world in which some central part of our meaning system suddenly disappears? I've played with the idea in thinking about having survived an atomic war which destroyed most humans, and all the basic infrastructures of everyday life. The problems one runs into even in such a game of imagination is to be consistent and being able to step far enough away to see what it is that really changes. In my day-dreaming imaginings I never went so far as to even dare to consider the inner changes in my person or the other survivors around me. It was much more than I could do to even anticipate and manage the physical problems of change and how to deal with them.

Jose Saramago presents us with exactly such a problematic, yet his masterful analysis deals not only with the physical aspects of change and how his characters deal with them, but he inters into the psychological realm and astounds us with his insights and brilliance.

A man is sitting at a traffic light one day waiting for the light to turn green and he suddenly goes blind. This is the "first blind man." Slowly this mysterious form of blindness, the like not known in the literature of modern medicine, spreads to the whole nation. As best we know, there is only one sighted person left in the realm. We follow a cast of fewer than 10 characters in detail. We have no names, only descriptors. After all one character tells us "blind people need no names." There is the first blind man, the first blind man's wife. The blind man had a seeming good semaritan who helps him home and but then steals his car and is thus called the man who had stole the car. There is the doctor whom he consults and the doctor's wife, the girl with dark glasses, the boy with the squint and the man with the black eye patch. There are a few others, but these become our key characters, later on adding the dog of tears.

In the early days of the white blindness in which each person seems only a white creamy mass, the government freaks out at the quick contagion of it and inters a large number of the blind in an old insane asylum. There, in scenes which are quite reminiscent of Golding's The Lord of the Flies, pure anarchy reigns and a gang sets itself up to control the government delivered food.

Soon however, the 7 central characters have escaped the asylum when it turns out that all the guards who are keeping them interred have themselves gone blind and they simply walk out into a world of all blind people.

All blind people that is, save one. The doctor's wife somehow remains sighted and she is able to give this small group the advantages that allows it to survive when others could not. She can locate places, keep them all in line and, most importantly, find food and water in a world gone blind.

What is this odd book of Jose Saramago? Is it an allegory? If so an allegory of what? Of the dependency of humans on basic systems of order in the manner of Thomas Hobbes? Is it a condemnation of humans as being only on the edge of civilization and being shown to be ready to plunge into barbarism at the least shaking of central systems of order? Or on a more positive note, is the tiny group of 7 the hopeful core that even in such catastrophic circumstances would maintain humanity and re-create a safer environment? Were this latter the case then the critic has a difficult time explaining the presence of the one sighted person who survives and leads. Or does this problematic suggest that leaders are essential to the continuation of the human species?

Or, abandoning the allegory theory, is this simply an astonishing tour-de-force of imagination, being just what it is literally and no more, the investigation of the logic of life when something such as sight disappears and the sighted woman is necessary as a sop since no other believable mode of survival would be easily available. This view would harmonize with the direction one finds in other Saramago novels especially The Stone Raft and The Gospel According to Jesus Christ, perhaps even of The Year of the Death of Ricardo Reis. Saramago seems to have a passion for playing with alternative realities and attending with care to the logic of the system he once sets up.

I believe I lean much more to this notion that we are to understand Blindness not as an allegory, but as an exploration of an alternative reality. On his view we are freer to remain inside the story as given and just marvel at how he unravels the story and develops not only the physical ramifications, but especially how he deals with the inner realities and changes in the character's minds. However, on this view we are left with the curious status of the doctor's wife's sight, and then the even more curious recurrence of the "special" dog which we had in The Stone Raft as well. Saramago seems to like dogs in nearly occult roles in his fantasies. This one, however, plays no central as the dog in The Stone Raft. Rather, it gets it name by licking away the tears of the doctor's wife when she breaks down in near despair on see what has happened to the blind city. The dog of tears remains with the group the rest of the tale, but seems to have no other role.

After just the first few pages I nearly lost my faith in Saramago. The blind man goes blind at the stop sign, gets taken home by the car thief and soon is taken to the doctor, who is an ophthalmologist, by his wife. I began to wonder -- how in the world can he sustain an entire moderately long novel as the story of this blind guy. Where could this go? What is there to build on? I suspected I may have had a weak Saramago novel in my hand. And then the thunderous second shoe drops, the doctor goes blind in the night. I simply gasped aloud on the subway I was riding when that happened. I knew I was now in for something odd, but I had no idea just how odd and soon people were falling into blindness with great rapidity and I was hooked on a new alternative world according to Saramago. The ending, which I won't mention was very unsatisfactory to me, but I'll leave that to the reader to discover and evaluate on his or her own.

Jose Saramago is one of the great masters of storytelling and fiction of our time. His language is impeccable and he plays with it often, calling attention to it, even interrupting the story to reflect on words and modes of expressing thoughts. The story itself is captivating and in the later sections when the group of 7 are wandering in this nightmare of a city where all are blind is one of the most frightful and even terrifying scenes I know in fiction. This is in no way a horror story, yet I can't imagine a novel in the genre of horror rising to the level of terror that Saramago strikes in us in these scenes of wandering bands of blind people struggling to find food and stay alive. It is a macabre and brilliant painting of pictures for the verbally sighted and yet another addition to the marvelous list of Saramago triumphs.

Special thanks to George Snedeker for this note:

I have just read your review of Saramago's BLINDNESS. as a visually impaired person, I have been trying to make sense of his use of blindness as a trope. blindness operates in his text as both an intertextual sign and as a referent. blindness represents limitation. this is true in the very obvious sense of the analogy between knowing and seeing. blindness also leads the characters to return to the state of nature. I have always been troubled by the doctor's wife. her eyes allow her to lead the others to safety. she is also necessary as the narrator of the story. without her, who would describe the events and scenes of the novel.

A more systematic review from George Snedeker

BETWEEN METAPHOR AND REFERENT:Reading Saramago's "Blindness" George Snedeker Sociology Program SUNY/College at Old Westbury

Jose Saramago received the Nobel Prize for Literature in 1998. Although several of his books were available in English translation, not many people in the United States had read his novels prior to the award. Soon his latest novel, Blindness, was on the New York Times Best-Seller List. If I had not previously read two of his earlier books, I would not have been much interested in reading an allegorical novel that uses blindness as its master sign.

Saramago uses a quotation from the Book of Exhortations as the epigram to Blindness: "If you can see, look. If you can look, observe". Near the end of the novel, when the blind people are getting their vision back, he has one of his characters remark:" I don't think we did go blind, I think we are blind, Blind but seeing, Blind people who can see, but do not see" (292). These two quotations indicate the political and philosophical intention of the novel. They indicate, but do not disclose it. The greatest problem with an allegorical novel like Blindness is that it grants too much freedom to the reader. It allows too many interpretations.

Saramago uses blindness as a metaphor for both personal misfortune and social catastrophe. The story begins when the first blind man loses his vision in his car while waiting for a traffic light to change. The man who helps him get safely home goes back and steals his car. The next day the wife of the first blind man takes him to see the eye doctor. Within a few days, the wife of the first blind man, the car thief, the doctor and all of the patients in his waiting room also go blind. The only character in the novel that miraculously avoids the affliction of blindness is the doctor's wife.

With a large number of people going blind quickly and with no apparent cause, public health officials panic and the blind are interned in a former mental hospital to protect the population from infection.

They are provided with food but are left to fend for themselves within the walls of the abandoned mental hospital. Soldiers keep watch and threaten to kill anyone who tries to escape.

The numbers of infected persons increases rapidly. New groups of blind people are imprisoned in the hospital. Among the new inmates are a group of hoodlums, one of whom possesses a gun. The hoodlums soon demand that the other internees pay for their food and provide them with women to fulfill their sexual desires. This outrage soon leads to a revolt. A few days later, the blind internees realize that the entire population of the city has gone blind and they leave the hospital in search of food.

As the narrative of Blindness progresses, the conditions of the blind continue to get worse. They find themselves in a society that no longer functions. Blind people roam the streets looking for food and shelter. After scavenging for days, they realize that soon it will be impossible to obtain enough nourishment to keep alive. While they are at the edge of despair their vision miraculously begins to return. The novel abruptly ends without making clear in what ways people have been transformed by the horrific experience of collective blindness.

As I mentioned earlier, the doctor's wife is the only character who does not go blind. She remains free from infection. This allows her to assist the group of blind people. Her eyes allow her to exercise a degree of control over the situation. It is she who kills the blind man with the gun. It is she who leads the blind in their search for food and shelter.

Blindness is clearly a sign of limitation in this novel. It causes the entire society to no longer function. It also places blind people in the condition of physical jeopardy and psychological torment. The society no longer functions because the blind are not able to provide the ordinary services that we are routinely dependent upon for survival: the production and distribution of food, water and electricity and the maintenance of the infrastructure of transportation and communication.

The central problem with Saramago's novel is that his master sign "blindness" is a floating signifier. No matter what his intention, the metaphor of blindness has a real referent. Readers of this novel are faced with an ambiguity, the relationship between the "symbolic" and the "real". The authorial voice of the novel and the critical response which has appeared in the mainstream press has occluded the problem of the referent. Saramago writes as if his metaphorical depiction of misfortune and catastrophe could somehow be innocent of the cultural meanings that are routinely associated with visual impairment. It is interesting to note that reviews which have appeared in the mainstream press fail to even consider that the use of blindness as a metaphor might pose a problem.

Reviewers have often made the comparison between Blindness and Camus' Plague, Kafka's Trial and Golding's Lord of the Flies. None of the reviews I have read have made the more obvious comparison to H.G. Wells' short story "The Country of the Blind". In this story, Wells uses blindness to represent a restricting society and the struggle of the individual against social conformity. Both Saramago and Wells use blindness as a sign of limitation because this idea is readily available. It is part of our common stock of cultural images. They use "blindness" for the same reason that Golding uses "children" in Lord of the Flies.

Like Camus, Saramago uses disease as a way of representing social and political crisis. Both authors emphasize the human response to social catastrophe. However, there is a problem with the representation of historical events by means of a medical model. In this representation, nature displaces the social and replaces it with an image of fate. As a consequence, blindness is defined as a physical condition.

Saramago's writings have often been discussed as an example of "magic realism". However, Blindness has more in common with Kafka's allegorical novels than it does with works by Gabriel Garcia Marquez or Salman Rushdie.

The fundamental problem posed by allegorical novels is how to locate their political and social meaning. Saramago provides his readers with few clues to guide interpretation. The story is set in an unnamed country, somewhere in the second half of the twentieth century. There are few identifying characteristics that provide a context for the events that transpire.

The epidemic of blindness takes place without any apparent cause; the disease spreads quickly and as the novel ends the blind are getting their vision back. Their recovery has as little explanation as the onset of blindness. The problem the reader is faced with is what to make of the metaphorical illness, the social catastrophe, and the miraculous recovery. What does it all mean?

Near the end of the book, Saramago has one of his characters suggest that perhaps they had never really been blind, that perhaps the sighted do not really see. If this is meant to be the underlying message of the novel it is, in fact, not a very original idea, since the analogy between "seeing" and "understanding" is one of the oldest ideas in Western philosophy. It is perhaps most clearly illustrated in Book 7 of The Republic, where Plato uses a visual metaphor to illustrate the limits of human understanding. He describes a cave where several people are seated in such a way that they cannot see the direct light of the fire. Instead, they can only see its distorted shadows upon the wall of the cave.

I suspect that Saramago is more interested in probing the human capacity to understand social reality than the Platonic concept of Absolute Truth. I wish he had chosen a better way of representing this quest.

Bibliography

Plato. 1961.The Collected Dialogues of Plato. Princeton: Princeton University Press

Saramago, Jose. 1997. Blindness. New York: Harcourt Brace

Wells, H. G. 1911. The Country of The Blind and Other Stories. London: T. Nelson

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BLINDNESS by Jose Saramago - Webster University

Inattentional blindness is the failure to notice a fully-visible, but unexpected object because attention was engaged on another task, event, or object.

This phenomenon is related to but distinct from other failures of visual awareness such as change blindness, repetition blindness, visual masking, and the attentional blink. In most cases, studies of inattentional blindness involve a single critical trial in which an object appears unexpectedly while observers are performing their task. At the end of the trial, observers are asked a series of questions to determine whether or not they saw the unexpected object.

The term inattentional blindness was coined by Arien Mack and Irvin Rock to describe the results of their extensive studies of the visual perception of unexpected objects. Many of their studies from the early 1990s culminated in their 1998 Book entitled Inattentional Blindness (Mack & Rock, 1998). In their canonical task, observers view a briefly-presented cross on a computer display and attempt to judge whether the horizontal or vertical arm of the cross is longer. On a critical trial, an additional shape appears in the display, and after the trial, observers are asked whether they noticed anything other than the cross on that trial. Subsequent trials examine whether observers notice the shape now that it is expected (they know it can appear). Such trials were described as divided attention trials. Finally, observers often complete one trial in which they are told to ignore the cross and to report anything they see (see Figure 1). This full attention trial serves as a control condition to demonstrate that the unexpected object was perceptible even if it was not perceived on the critical trial. Using this approach, Mack, Rock, and their students and colleagues showed that people often miss the unexpected shape on the critical trial, even when it was a unique color and appeared for 200ms. Noticing rates typically ranged from 25-75% depending on the condition.

Although Mack and Rock coined the term inattentional blindness, earlier work had explored similar failures of awareness under conditions of selective attention. In perhaps the most prominent early demonstrations of this phenomenon, Ulric Neisser and his colleagues (Neisser, 1979; Neisser & Becklen, 1975) used a selective looking task to explore the role of attention in the detection of unexpected events. Their task was a visual analogue of earlier dichotic listening methods in which people often failed to notice the content of speech presented to one ear when they were actively focusing attention on speech presented to the other ear (e.g., Moray, 1959). In the studies by Neisser and colleagues, observers viewed two distinct, superimposed videos of people performing simple actions such as passing a basketball or playing a hand-slapping game. When observers focused attention on one of the events, they often failed to notice an unexpected event occurring in the other. For example, when counting the number of times several people passed a basketball while ignoring a hand-slapping game, they often failed to notice when the people in the hand-slapping stopped and shook hands (Neisser & Becklen, 1975). Recent replications and extensions of this approach by Simons and Chabris (1999) showed that such sustained inattentional blindness occurs even when the unexpected object is fully visible and the displays are not superimposed. In their study, participants counted basketball passes by players wearing white shirts and ignored passes made by players wearing black. Under these conditions, approximately 50% of observers failed to notice when a person in a gorilla suit entered the display, stopped and faced the camera, thumped its chest, and exited on the far side of the display (see movies at http://www.dansimons.com/videos.html).

More recent studies of inattentional blindness have explored how aspects of the task and stimuli contribute to inattentional blindness and the detection of unexpected objects: the role of expectations in the detection of unexpected objects (Most et al, 2005), the role of visual similarity of the unexpected objects to the attended and ignored items in the display (Most et al, 2001), the role of visual distinctiveness of the unexpected object, and the role of spatial proximity of the unexpected object to the focus of attention (Newby & Rock, 1998; Most et al, 2000). Other recent studies have examined how differences in the observers affect detection, including the effects of alcohol consumption (Clifasefi et al, 2006) or expertise in the primary task (Memmert, 2006).

All of the following criteria must hold to classify a failure of awareness as inattentional blindness as opposed to a different type of failure of awareness. Note that not all failures of awareness that result from distraction or inattention to a stimulus constitute inattentional blindness.

Traditionally, inattentional blindness refers specifically to the failure to notice unexpected objects. Some recent studies have demonstrated failures to notice objects that occur on many trials due to attentional engagement on a primary task. In such cases, the critical objects are expected, but observers fail to report them because they are engaged in another task. Although such failures of awareness can be attributed to attentional engagement, they do not precisely constitute examples of inattentional blindness. When a critical stimulus appears repeatedly during an experiment, observers do have a reason to look for it (they will be asked about it). Consequently, it might be attended, just not sufficiently to produce awareness of it. Such failures of awareness might be due to insufficient attention rather than inattention. The unexpected nature of the critical stimulus is what differentiates inattentional blindness from other failures of awareness due to distraction or attentional failures (e.g., the attentional blink).

Conclusions from studies of inattentional blindness are premised on the idea that a failure to report an unexpected stimulus results from a failure to see that stimulus. In principle, though, people might fail to report the unexpected stimulus even if they did see it they could simply forget that they saw it by the time they are asked about it. That is, they have inattentional amnesia rather than inattentional blindness (Wolfe, 1999). Differentiating these alternatives might be impossible because questioning inherently occurs after the event, leaving open the possibility of forgetting. Whether or not the inattentional amnesia explanation is more plausible or palatable is a matter of debate. For the amnesia account to hold, observers would have to consciously perceive the unexpected object and then forget that they saw it, something that might be less plausible when the unexpected object is particularly distinctive or unusual (e.g., a person in a gorilla suit).

Another alternative to the inattentional blindness account is that observers see the critical object in the display but do not process it extensively and consequently do not retain it. In essence, they experience inattentional agnosia (see Simons, 2000). They might see that there is something in the display, but not identify it as a gorilla. In fact, they might not identify it as a coherent object at all. Under this explanation, something is perceived, but it is not perceived as some thing. Because it is not encoded as a thing, it is not remembered and reported after the display is removed. However, evidence that the critical object can prime a subsequent response suggests that it is processed to some extent, even when it is not reported.

Change blindness refers to the failure to notice something different about a display whereas inattentional blindness refers to a failure to see something present in a display. Although these two phenomena are related, they are also distinct. Change blindness inherently involves memory people fail to notice something different about the display from one moment to the next; that is, they must compare two displays to spot the change (see Simons & Rensink, 2005). The signal for change detection is the difference between two displays, and neither display on its own can provide evidence that a change occurred. In contrast, inattentional blindness refers to a failure to notice something about an individual display. The missed element does not require memory people fail to notice that something is present in a display. In a sense, most inattentional blindness tasks could be construed as change blindness tasks by noting that people fail to see the introduction of the unexpected object (a change it was not present before and now it is). However, inattentional blindness specifically refers to a failure to see the object altogether, not to a failure to compare the current state of a display to an earlier state stored in memory.

Studies of inattentional blindness demonstrate that people fail to notice unexpected objects in a display. Or, more precisely, that they fail to report having noticed an unexpected object. The information from the unexpected object is filtered from awareness by the time people are asked about it. However, it is unclear how much processing of the unexpected object occurs before this filtering. In its strongest form, the word "blindness" implies that the information is processed minimally if at all. However, other evidence suggests that the unexpected object is processed and that it can influence perception. For example, when the unexpected object involves the grouping of background dots in a display, the unreported grouping can affect judgments of line length in the Mueller-Lyer illusion (Moore & Egeth, 1997). And, as for early studies of dichotic listening (Treisman, 1964), some stimuli apparently are less subject to inattentional blindness. For example, observers typically fail to see common words in the Mack and Rock task, but they do see their own name when it appears unexpectedly (Mack & Rock, 1998). Observers also show some priming from unreported words as evidenced by a tendency to complete word fragments with the unreported word rather than other more common words (Mack & Rock, 1998). These findings suggest that the unexpected object is processed, possibly to a semantic level, even when it is unreported. If so, they also suggest that the inattentional agnosia explanation is wrong, at least at some level semantic processing implies that the object was identified at some level of the visual system.

Evidence that the unreported stimulus is processed to some extent is reminiscent of other research on subliminal perception, the idea that unseen stimuli exert an influence on perception or possibly behavior. However, care must be taken to draw strong inferences about implicit or subliminal perception from the inattentional blindness tasks. Inattentional blindness tasks rely on a single critical trial to determine whether or not an unexpected object was consciously perceived. However, the inference that it was not perceived depends on a report after the trial, and such reports are subject to many influences other than just whether or not the object was seen. For example, some people might be more hesitant to report an incredible object when they lack certainty that they saw it (in signal detection terms, they respond conservatively). If so, they might not report the unexpected object even if they have some inkling that something might have been present in the display. In other words, they might have consciously perceived the unexpected object, but been hesitant to say so definitively. With only one critical trial, the inattentional blindness task is poorly designed to discriminate between the ability to detect the stimulus and biases in the tendency to report the stimulus. That said, the unexpected object does fall below a subjective threshold for awareness in that people do not report it. And, that subjective threshold for awareness may be practically important, even if observers objectively saw something.

Evidence for inattentional blindness comes mostly from relatively simple laboratory tasks, but the phenomenon likely has many daily analogues. For example, automobile accident reports frequently report driver claims that they looked but failed to see the other vehicle. Many collisions between cars and motorcycles involve cars turning in front of an oncoming motorcycle, with the car driver not seeing the motorcyclist. Given that in many contexts, motorcycles are less common that cars, inattentional blindness is more likely. Critically, the difficulty of the primary task in an inattentional blindness task increases the probability that people will miss the unexpected object. In practical terms, the more people focus on aspects of their visual world other than the detection of unexpected objects, the less likely they are to detect such objects. Recent evidence suggests that talking on a cell phone, for example, dramatically increases the probability of missing an unexpected object (Scholl et al, 2003).

Although inattentional blindness constitutes a limit of the visual system, it also illustrates a critical aspect of visual processing. Specifically, it reveals the role of selective attention in perception. Inattentional blindness represents a consequence of this critical process that allows us to remain focused on important aspects of our world without distraction from irrelevant objects and events. Only when those unselected aspects of our world are both unexpected and important does inattentional blindness have practical consequences. And, inattentional blindness itself may be useful in some contexts. For example, by guiding selective attention to one part of a display, it is possible to reduce the visual quality of a different part of the display with minimal consequence, possibly allowing greater visual compression in motion sequences (Cater et al, 2002).

Internal references

Attention, Cognition, Models of Consciousness, Neural Correlates of Consciousness, Consciousness and Attention, Visual Cognition, Visual Attention, Change Blindness

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Inattentional blindness - Scholarpedia

Inattentional blindness is an inability to perceive something that is within one's direct perceptual field because one is attending to something else. The term was coined by psychologists Arien Mack and Irvin Rock, who identified the phenomenon while studying the relationship of attention to perception. They were able to show that, under a number of different conditions, if subjects were not attending to a visual stimulus but were attending to something else in the visual field, a significant percentage of the subjects were "blind" to something that was right before their eyes.

Because this inability to perceive, this sighted blindness, seemed to be caused by the fact that subjects were not attending to the stimulus but instead were attending to something else ... we labeled this phenomenon inattentional blindness (IB).*

Mack and Rock go on to argue that, in their view, "there is no conscious perception without attention."

Others, such as U. Neisser, D. Simons, and C. Chabris, have replicated and extended the work of Mack and Rock with experiments that have subjects attending to a specific task while watching a film, such as counting how many times a basketball is passed from one team member to another, while someone walks through the scene carrying an umbrella or wearing a gorilla suit. A surprisingly large percentage of subjects do not perceive something as obvious as a person in a gorilla suit moving through the scene they are observing, if they are attending to something else in their visual field. (Several examples of these experiments can be viewed on the Simons Lab page of the University of Illinois.)

Inattentional blindness may explain, for example, how a pilot with an interest in crop circles could fly right over one without even noticing it. The pilot had flown to see a recently discovered crop circle near Stonehenge. After visiting the site, he flew back to the airport to refuel before setting off on a trip that took him back over the site he had just visited. On the return flight he noticed another crop circle near the one he had visited earlier in the day and swears that the new circle was not there just forty-five minutes earlier. The new circle is very elaborate and could not have been produced by human hoaxers in such a short time. He concludes that some mysterious force must have been at work. Perhaps, but it seems more likely that the pilot experienced inattentional blindness when he was flying to the airport. He was focused on other tasks when he flew over the site and didnt notice what was right beneath him all the time. (See "Crop Circles - Quest for Truth.")

Research by Chabris and Simons indicates that inattentional blindness is a "necessary, if unfortunate, by-product of the normal operation of attention and perception" (2010, p. 38). They point out that even radiologists, who are highly trained experts at detecting visual signs of medical problems, "can still miss subtle problems when they 'read' medical images." This may explain why my dentist didn't see a crack in one of my teeth on an x-ray until I started to complain about the pain in a particular area. To eliminate inattentional blindness, we'd have to eliminate focused attention. That would not be a good idea. Even worse would be the condition of being able to attend to everything in our sensory field at once. It would drive us mad.

Research also shows that training people to improve their attention abilities may do nothing to help them detect unexpected objects. "If an object is truly unexpected, people are unlikely to notice it no matter how good (or bad) they are at focusing attention" (Chabris and Simons: 2010, p. 32). Remember this the next time you're at the airport watching the transportation security screener do his or her job. It should not be surprising to find that these folks miss a lot of contraband planted by their bosses to test them. You might also remember this: there is no scientific evidence to support the belief that driving while talking on a hands-free phone is safer than driving while holding a cell to your ear. Worse, both have about the same effect as driving under the influence of alcohol (Chabris and Simons: 2010, pp. 22-26).

See also change blindness, confabulation, and my review of The Invisible Gorilla.

further reading

books and articles

Chabris, Christopher and Daniel Simons. 2010. The Invisible Gorilla: And Other Ways Our Intuitions Deceive Us. Crown.

Simons, Daniel J. and Christopher F. Chabris. (1999). "Gorillas in our midst: sustained inattentional blindness for dynamic events." Perception, 1999, volume 28, pages 1059-1074.

Mack, Arien and Irvin Rock. (2000). Inattentional Blindness. MIT Press.

websites

The Invisible Gorilla blog

Simons Lab (teachers may be interested in purchasing the DVD the VCL sells)

Inattentional Blindness - An Overview by Arien Mack & Irvin Rock

David Chalmers's list of papers on change blindness and inattentional blindness

The Choice Blindness lab

news

AAA: Voice-to-text devices worse driver distraction than cell phones An in-depth scientific study from AAA finds that using voice-to-text electronic devices is a far greater distraction for drivers than talking on cell phones, even if they are hands free.

Why Even Radiologists Can Miss A Gorilla Hiding In Plain Sight by Alix Spiegel - 83 percent of the radiologists didn't see the gorilla in the X-ray.

Study reveals how memory load leaves us blind to new visual information "The new results reveal that our visual field does not need to be cluttered with other objects to cause [inattentional blindness] and that focusing on remembering something we have just seen is enough to make us unaware of things that happen around us."

gorillas, working memory, and the media by Daniel Simons The news media doesn't get it quite right about a new study from the University of Utah. Typical is this Eureka alert:

University of Utah psychologists have learned why many people experience "inattention blindness" the phenomenon that leaves drivers on cell phones prone to traffic accidents and makes a gorilla invisible to viewers of a famous video. The answer: People who fail to see something right in front of them while they are focusing on something else have lower "working memory capacity" a measure of "attentional control," or the ability to focus attention when and where needed, and on more than one thing at a time.

"The media is reacting to the finding that, under some conditions, differences in working memory capacity predict noticing of an unexpected gorilla. They over-generalize the finding to suggest that people who are high in working memory capacity are immune to inattentional blindness....Any scientist reading the journal article would recognize that the correlation between working memory and noticing is imperfect and would separate speculative conclusions from definitive results. Unless the press release makes those limitations explicit, the media will not either. Unless the press release explicitly identifies the limited scope and imperfect correlation and flags speculation as such, an untrained reader (or headline writer) will naturally infer that the result and the speculation are one and the same. In this case, they will infer that working memory differences explain inattentional blindness in its entirety. By not reining in the speculation, the release suggests that the working memory is the primary (if not the only) reason that some people notice and some people miss unexpected objects."

Ghost busters, parapsychology, and the first study of inattentional blindness "More than 50 years ago, Tony Cornell, a parapsychology researcher, decided to test how people would react upon seeing him dressed as a ghost. Would they experience him as a "real" ghost or as something more mundane?....Each night, Cornell or his assistants dressed in a white sheet and strolled down a path, making various hand gestures before shedding the sheet 4.5 minutes later. Other assistants observed how many people were "in a position to observe the apparition." His finding: "although it was estimated that some 70-80 persons were in a position to observe the apparition, not one was seen to give it a second glance or to react in any way." That's true even though a number of cows apparently followed the ghost around."Last updated 14-Jan-2014

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inattentional blindness (aka inattention blindness)- The ...

In 2012, when Tyler Millard wrote the song Alivenow available on iTunes, with proceeds going to the Foundation Fighting Blindnesshe was having a rough time. Since being diagnosed with retinitis pigmentosa (RP) seven years earlier, hed lost enough eyesight to have to give up his plans to teach math. Hed also taken up the guitar and was singing and songwriting, although the gigs were few and far between. Continue Reading

One of the biggest challenges in overcoming rare retinal diseases is, well, that theyre rare. Theres limited information about the conditions in humans, making it difficult for researchers to understand why they cause blindness and develop vision-saving treatments. Continue Reading

The Foundation Fighting Blindness scientists, donors and volunteers made 2015 an outstanding year in our fight against blindness. As I tabulated the years top 10 research advancesall made possible through FFB fundingI realized that eight are for clinical trials of emerging therapies that are launching or underway. Continue Reading

Its holiday time, the giving season, when people not only buy gifts for family, friends and co-workers, but also donate to worthy causesof which there are many. But, if youll permit me, Id like to make a pitch for the Foundation Fighting Blindness (FFB), which happens to be offering a Holiday Board Match, meaning every donation is doubled. Continue Reading

If youre a young or middle-aged adult who enjoys being outside in the bright sunshine, youre probably not thinking about the risk for going blind from age-related macular degeneration (AMD). But according to a new study published in the journal Retina, you should be. Continue Reading

Were approaching a critical milestone in the fight against blinding retinal diseases, and it has the potential to tremendously boost and accelerate the advancement of virtually all gene therapies in development for dozens of inherited retinal diseases.

Sometime in 2016, Spark Therapeutics will request marketing approval from the U.S. Food and Drug Administration (FDA) for its landmark gene therapy for retinal conditions caused by mutations in the gene RPE65, namely certain forms of Leber congenital amaurosis and retinitis pigmentosa. Continue Reading

Gordon Gund, whos held in extremely high esteem by people inside and outside the Foundation Fighting Blindness (FFB), has been completely blind for decades. He lost his eyesight to a disease called retinitis pigmentosa in his thirties. Not that it slowed him down much. Among other accomplishments, hes been a financier, venture capitalist, sports-team owner and sculptor. And, of course, hes a co-founder of FFB and its chairman of the board. Continue Reading

I am delighted to welcome Valerie Navy-Daniels to the Foundation Fighting Blindness family. As our new chief development officer, she is overseeing all of our fundraising programs including events, major gifts and membership as well as communications and marketing. As many of you know, most of our research is funded by these fundraising programs, so her role is critical to the success of our mission of saving and restoring vision. Continue Reading

Many people with retinal conditions such as retinitis pigmentosa (RP) and age-related macular degeneration dont think they can donate their eyes after theyve passed away. They cant imagine anyone would want eyes that didnt work well. But in reality, affected eyes are in big demand. Continue Reading

X-linked retinitis pigmentosa (XLRP) is an inherited retinal disease causing significant vision loss, sometimes complete blindness, in males. Females are often considered to be unaffected carriers of the condition, with a 50 percent chance of passing XLRP to their sons. Continue Reading

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Eye on the Cure - Blog of the Foundation Fighting Blindness

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Job Classification

In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

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Blindness - Medical Disability Guidelines

Katie Abbott ... key craft service: Canada Paulo Abel ... daily location manager: Brazil Ivan Abelma Girquinto ... armorer: prop weapons, Brazil Cristina Abi ... production coordinator: Brazil & Uruguay Kim Jon Ah ... stand-in: Uruguay Philip Akin ... adr loop group Micaela Alaniz ... unit production trainee: Brazil Ilona Alfard ... esthetician: Canada Cynthia Amsden ... unit publicist: Canada Arrigo Araujo ... production trainee: Brazil Felipe Arnaut Cappellini ... production runner: 02 Filmes Daniela Antonelli Aun ... unit production secretary: Brazil Gregorio Azarrez ... unit production trainee: Uruguay Maria Eugenia Aznarez Morelli ... first assistant accountant: Uruguay Juan Fco. Baldomir ... legal services: Uruguay Marina Ballarin ... stand-in: Brazil (as Marina Balarin) Reginaldo Barbosa ... set assistant: Brazil Pedro Barcia Lucas ... assistant set manager: Uruguay Tom Barnett ... adr loop group Klaus Bartram ... assistant location manager: Uruguay Andre Batista ... firts set manager assistant, set manager (second unit) / set assistant: Brazil Chris Bell ... business affairs coordinator: Rhombus Media Marcela Bellini ... assistant unit production secretary: Uruguay Elena Berdichevsky ... stand-in: Canada Robert Bockstael ... adr loop group Patricia Dalla Bohr ... personal assistant: Brazil Sandie Bornstein ... accountant: Rhombus Media Eduardo Braga ... personal assistant: Brazil Gal Buitoni ... clearance coordinator: Brazil & Uruguay Emma Campbell ... adr loop group Juan Campokar ... legal services: Uruguay Giovani Canhotto ... set manager: Brazil & Uruguay (as Canhoto) Aruan Canolla ... blindness coach trainee: Brazil Rafael Carmona ... daily location manager: Brazil Juliette Caron ... french subtitles by Gastn Casas ... assistant location manager: Uruguay Inara Censig ... stand-in: Brazil Ivanna Cestau ... second unit production assistant: Uruguay Kevin Cheng ... clearance coordinator Andy Condon ... technical consultant Marcelo Cotrim ... location manager: Brazil Glauco Cruz ... security coordinator: Brazil Nadia Day ... production coordinator: Canada Maximiliano Destro ... stand-in: Uruguay Shaun Dewet ... cast liaison Sonya Di Rienzo ... travel coordinator: Canada Maria Jos Diaz Dutra ... assistant location manager: Uruguay Pedro Duran ... stand-in: Brazil Fiorella Durante ... personal assistant: Uruguay Christian Duurvoort ... acting coach: blindness Patricia Fagan ... adr loop group Maria Noel Fernandez Brez ... unit production secretary: Uruguay David Ferrant ... stand-in: Canada Celia Regina Ferreira ... production coordinator: 02 Filmes Figueroa ... studio coordinator: 02 Filmes Focused on Food ... craft service Liane Fraccaroli ... assistant: Andrea Barata Rabeiro, 02 Filmes Tetsu Fujimura ... project consultant: Filosophia Koji Fujino ... financial advisor: T.Y.Limited Ron Gabriel ... adr loop group Ricardo Gorodetcki ... title designer / title designer: main and end titles Robin Greavette ... assistant location manager: Canada Richard Greenblatt ... adr loop group Indira Guha ... business and legal affairs: Telefilm Canada David B. Guthrie ... production assistant: Rhombus Media (as David Guthrie) Rhonda Hall ... stand-in: Canada Ginette Hamel ... on-set physiotherapist: Canada Nigel Hartwell ... production assistant Edwin Hawkeswood ... set production assistant: Canada (as Eddie Hawkeswood) Michael Healey ... adr loop group John Hirata ... stand-in: Uruguay Ryan Hollyman ... adr loop group Elise Hori ... stand-in: Brazil Daniel Horvat ... key production accountant Yuka Hoshino ... marketing executive: GAGA Communications Rogrio Jacyntino ... production secretary: Brazil & Uruguay John Jarvis ... adr loop group Winnifred Jong ... script supervisor Dbora Kaganovicius ... unit production assistant: Uruguay (as Deborah Kaganovicius) Ronan Keane ... first assistant accountant payroll: Canada Kathy Kerrin ... accountant: Bee Vine Pictures Joanna King ... office and distribution coordinator: Rhombus Media Takahiro Kobayashi ... legal consultant: IFF/CINV Toshio Kondo ... advisor: Bee Vine Pictures Alex Kontsalakis ... first assistant accountant: Canada Kevin Krikst ... assistant: Niv Fichman, Rhombus Media Mary Krohnert ... adr loop group Pablo Laporte De Armas ... unit production assistant: Uruguay Esli Leal ... financial coordinator: 02 Filmes Fernanda Leite ... assistant location manager: Brazil Joo Leite ... roadie Joao Mauricio Leonel ... set assistant: Brazil Erika Levi ... personal assistant: Uruguay George P. Lin ... accountant: Bee Vine Pictures (as George Lin) Simone Lindo ... second accounting assistant: Canada (as Simone J. Lindo) Leonardo Luppi ... stand-in: Uruguay Kate Lynch ... adr loop group Eduardo Lyon ... assistant: Fernando Meirelles, 02 Filmes Santiago Lpez ... assistant location manager: Uruguay Maria Victoria Mach Bengor ... second unit production assistant: Uruguay Maria Leticia Macorin ... location manager trainee: Brazil Lilit 'Hank' Malins ... location manager: Canada Nozomi Masuka ... script translator: Japan Hiroyuki Matsunaga ... executive assistant: Mr. Yoda, T.Y.Limited Yuka Matsushima ... financial affairs: IFF/CINV Tsuyoshi Matsushita ... promotion director: GAGA Communications Adam Meaden ... location support Marina Medeiros ... assistant acting coach: blindness, Brazil & Uruguay Murilo Meola ... stand-in: Brazil Rafal Mickiewicz ... stand-in: Canada Luiza Morandini ... personal assistant: Brazil Pedro Morelli ... assistant acting coach: blindness Mitsuya Morita ... director of business affairs: IFF/CINV Akiko Nagayo ... financial affairs: IFF/CINV Cludia Nazar ... administrative coordinator: 02 Filmes Kasumi Nishi ... legal consultant: IFF/CINV Amanda Nunes Lima ... first assistant accountant: Brazil & Uruguay Satomi Odake ... business coordinator: GAGA Communications Vital Pasquale ... assistant title designer Thoms Douglas Pastn ... production runner: 02 Filmes Maren Pedrozo ... stand-in: Uruguay Valentina Peirano ... second assistant accountant: Uruguay Josy Peres ... personal assistants coordinator: Brazil & Uruguay Shannon Perreault ... adr loop group Trina Petrik ... craft service: Canada Mimma Petrovic ... reference research: photographs Jordan Pettle ... adr loop group Joaquin P. Peyrou ... assistant location manager: Uruguay Ins Peagaricano ... location manager: Uruguay (as Ines Peagaricano) Pablo Pen ... set manager: Uruguay Henrique Pires ... reference researcher: 02 Filmes Mariana Prado ... personal assistant: Brazil Tina Marie Remedios ... production accountant Maria Helena Reneiro ... craft service: Brazil Jos Carlos Riscala ... production runner: 02 Filmes Brenda Robins ... adr loop group Gabriel Rodrigeuz Puig ... production coordinator: Uruguay Alvaro Rodrguez ... stand-in: Uruguay Ryan Rogerson ... adr loop group Alexandre Rossi ... animal wrangler: Brazil & Uruguay Richard Rotter ... production assistant: Canada Jim Russell ... legal services Stephen L. Saltzman ... legal services (as Steven Saltzman) Fernanda Sanjurjo Olavarra ... personal assistant: Uruguay Masayuki Sano ... business coordinator: Asmik Ace Entertainment Carolina Sastre ... unit production assistant: Uruguay Rafaeda Schmidt ... unit production trainee: Brazil Ed Segeren ... technical consultant Fabiana Sequeiros ... stand-in: Uruguay Emma Sereny-Johnson ... production assistant: Canada Giannina Settin ... personal assistant: Uruguay Takashi Shinomiya ... legal consultant: IFF/CINV Skye Siriunrs ... set medic: Canada Victoria Snow ... adr loop group Karie Snyder ... production secretary: Canada Darryl Stawychny ... production assistant David Storch ... adr loop group Dominic Stubbs ... accountant: Rhombus Media Alan Sutton ... fire safety coordinator Tomoyuki Suzuki ... legal consultant: IFF/CINV Kei Takahashi ... business coordinator: Asmik Ace Entertainment Charles Taylor ... firearms wrangler: Canada Drew Taylor ... location assistant: Canada Hironori Terashima ... executive business coordinator: Asmik Ace Entertainment Masao Teshima ... corporate executive: Asmik Ace Entertainment Mauro Theodoro ... stand-in: Brazil Fernando Tiezzi ... assistant blindness coach: Brazil Guillermo Daniel M. Troha ... assistant location manager: Uruguay Adrian Truss ... adr loop group Martin Ubillos ... second unit production assistant: Uruguay Yasuhide Uno ... corporate executive: GAGA Communications Milagros Uria Strauch ... assistant unit production secretary: Uruguay Mirella Valente ... assistant location manager: Brazil Laura Varela Mller ... unit production assistant: Uruguay Dolores Vargas ... second assistant accountant: Uruguay Bruno Vecchi Ricci ... production runner: 02 Filmes Al Vrkljan ... firearms wrangler: Canada (as Alan Vrkljan) Masazumi Watanabe ... director of creative affairs: IFF/CINV Wendy Williamson ... assistant production coordinator: Canada Sherry Wolfson ... travel assistant Fernando Hitoshi Yagyu ... production runner: 02 Filmes Michiko Yamaguchi ... business coordinator: GAGA Communications Celso Yamashita ... blindness coach: Brazil & Uruguay Kazuya Yamashita ... business affairs: Filosophia Mandela Youga ... craft service: Brazil Marcelo Yuar ... stand-in: Brazil Mara Zanocchi ... location manager: Uruguay (as Maria Zanocchi) Phillip Zelante ... first assistant set manager: Brazil Ricardo Zrnini ... assistant animal wrangler: Brazil & Uruguay Lucas Kater ... set assistant: Brazil (uncredited) Vanessa King ... assistant to ms. moore (uncredited)

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Blindness (2008) - Full Cast & Crew - IMDb

Change blindness is a surprising perceptual phenomenon that occurs when a change in a visual stimulus is introduced and the observer does not notice it. For example, observers often fail to notice major differences introduced into an image while it flickers off and on again.[1] People's poor ability to detect changes has been argued to reflect fundamental limitations of human attention. Change blindness has become a highly researched topic and some have argued that it may have important practical implications in areas such as eyewitness testimony and distractions while driving.

Outside of the domain of psychology, phenomena related to change blindness have been discussed since the 19th century.[2] When film editing was introduced in movies, editors began to notice that changes to the background were not noticed by those watching the film.[2] Going back much earlier, William James (18421910) was the first to mention the lack of ability to detect change in his book Principles of Psychology. (1890) [2]

Research on change blindness developed from investigation in other phenomena such as eye movements and working memory.[2] Although individuals have a very good memory as to whether or not they have seen an image, they are generally poor at recalling the smaller details in that image.[3][4] When we are visually stimulated with a complex picture, it is more likely that individuals retain only a gist of an image and not the image in its entirety.

The laboratory study of change blindness began in the 1970s within the context of eye movement research. McConkie conducted the first studies on change blindness involving changes in words and texts; in these studies, the changes were introduced while the observer performed a saccadic eye movement. Observers often failed to notice these changes.[5]

In the late 1980s, the first clear experimental demonstration was published showing very poor change detection in complex displays over brief intervals without eye movements being involved. Pashler (1988) showed that observers were poor at detecting changes introduced into arrays of letters while the display was flickered off and on, even if the offset was as brief as 67 milliseconds (although offsets briefer than that produced much more effective change detection). Pashler concluded by noting how odd it was that people generally report having a "clear sense of apprehending the identities and locations of large numbers of objects in a scene" (p.377), and that given this introspective sense, it seemed quite surprising how poor is their detection of changes.[2]

With the rise of the ability to present complex, real-world images on a computer screen, Dr. George McConkie, in the early 1990s, as part of the new initiatives of the new Beckman Institute for Advanced Science and Technology, began a renewed attempt to investigate why the world looked stable and continuous despite the shifting retinal input signal that accompanied each saccade.[6][7] This research began when John Grimes and Dr. George McConkie (1996) began to use actual photographs to study visual stability.[8] This development in change blindness research was able to show the effects of change blindness in more realistic settings.[9] Additionally, further research stated that rather large changes will not be detected when they occur during saccadic movements of the eye. In the first experiment of this kind, in 1995, Blackmore et al forced saccades by moving the image and making a change in the scene at the same time.[10] Observers ability to detect the changes fell to chance. The effect was stronger using this method than when using brief grey flashes between images, although subsequent research has mostly used grey flashes or masking stimuli. Another finding based on similar studies stated that a change was easily picked up on by participants when the eye was fixated on the point of change. Therefore, the eye must be directly fixated on the area of change for it to be noticed. This was called the saccade target theory of transsaccadic memory of visual stability.[6][7][11] However, other research in the mid-1990s has indicated that individuals still have difficulty detecting change even when they are directly fixated on a particular scene. A study by Rensink, ORegan, & Clarke demonstrated that change blindness can have an effect even if the eye was fixated on a scene. In this study, a picture was presented followed by a blank screen or masking stimulus, which was followed by the initial picture with a change. The masking stimulus almost acts like a saccadic movement of the eye which makes it significantly more difficult for individuals to detect the change.[9] This was a critical contribution to change blindness research because it demonstrated that a change can remain unnoticed with the smallest disruptions.

Research on change blindness proceeded one step further into practical applications of this phenomenon. For example, there does not have to be a masking stimulus in order for individuals to miss a change in a scene. Individuals often take significantly longer to notice certain changes if there are a few small, high contrast shapes that are temporarily splattered over a picture.[12] This method for testing change blindness is called mudsplashes.[12] This method is particularly relevant to individuals driving in a car when there is a visual obstruction on the windshield. This obstruction may impair an individuals ability to detect a change in their environment which could result in severe negative consequences while driving.

Research indicates that detecting changes in a change blindness task is easier when items are holistically processed, such as faces. Individuals notice a change faster when required to detect changes in facial features than when required to detect changes in images of houses.[13] However, individuals are better at identifying the nature of the change in houses.[13]

Other researchers have discovered that mental processing in change blindness begins even before the change is presented. More specifically, there is increased brain activity in the parietal-occipital and occipital regions prior to the emergence of a change in a change blindness task.[14]

Researchers have also indicated there is a difference in brain activity between detecting a change and identifying change in an image. Detecting a change is associated with a higher ERP (Event-related potential) whereas identifying change is associated with an increased ERP before and after the change was presented.[15]

Additional research using fluctuations in ERPs (Event-related potentials) has observed that changes in pictures (change blindness) are represented in the brain, even without the perceivers conscious awareness of the change.[16]

Lucid dreaming occurs when one realizes that the events experienced within a dream are bizarre or would not occur in ones waking life.[17] As such, the inability to notice the bizarre nature of the dream has been coined as an example of change blindness, also known as individuals who are non-lucid dreamers. However, a recent study found that lucid dreamers did not perform better on a change blindness task than non-lucid dreamers.[17] Therefore, the relation between lucid dreamers and change blindness has been discredited to some degree.

Another interesting area of research is the decreased susceptibility to change blindness when individuals are placed in teams. Although change blindness is still observed within teams, research has indicated that changes between images are noticed more when individuals work in teams as opposed to individually.[18] Both teamwork and communication assist teams in correctly identifying changes between images.[18]

Another recent study looked at the relation between expertise and change blindness. Physics experts were more likely to notice a change between two physics problems than novices.[19] It is hypothesized that experts are better at analyzing problems on a deeper level whereas novices employ a surface-level analysis. This research suggests that observing the phenomenon of change blindness may be conditional upon the context of the task.

Cognitive psychologists expanded the study of Change Blindness into decision-making. In one study, they showed participants ten pairs of faces and asked them to choose which face was more attractive. For some pairs, the experimenter used sleight of hand to show participants a face they had NOT chosen. Only 26% of subjects noticed the mismatch between their choice of face and the different face they were shown instead. The experimenters tested pairs of faces that were either high in similarity or low in similarity, but the detection rate was no different between those conditions. Subjects were also asked to give reasons why they had chosen a face (although due to the sleight of hand they actually hadn't chosen it). Despite the mismatch, subjects gave responses that were comparable in emotionality, specificity, and certainty for faces they had or had not actually chosen.[20] Further research has showed that the failure to detect mismatches between intention and outcome exists in consumer product choices [21] and in political attitudes.[22]

This method was used in the first, 1995, experiment. A change is made in an image at the same time as the image is moved in an unpredictable direction, forcing a saccade. This method mimics eye movements and can detect change blindness without introducing blank screens, masking stimuli or mudsplashes.[10]

In this paradigm, an image and an altered image are switched back and forth with a blank screen in the middle.[1] This procedure is performed at a very high rate and observers are told to click a button as soon as they see the difference between the two images.[1] This method of studying change blindness has helped researchers discover two very important findings. The first finding is that it usually takes a while for individuals to notice a change even though they are being instructed to search for a change.[1] In some cases, it can even take individuals over one minute of constant flickers to determine the location of the change. The second important finding is that changes towards the middle of a picture are noticed at a faster rate than changes on the side of a picture.[1] Although the flicker paradigm was first used in the late 1990s, it is still commonly used in current research on change blindness and has contributed to current knowledge on change blindness.

Individuals who are tested under the forced choice paradigm are only allowed to view the two pictures once before they make a choice.[9] Both images are also shown for the same amount of time.[9] The flicker paradigm and the forced choice detection paradigm are known as intentional change detection tasks, which means that the participants know they are trying to detect change. These studies have shown that even while participants are focusing their attention and searching for a change, the change may remain unnoticed.

Mudsplashes are small, high contrast shapes that are scattered over an image, but do not cover the area of the picture in which the change occurs. This mudsplash effect prevents individuals from noticing the change between the two pictures.[12] A practical application of this paradigm is that dangerous stimuli in a scene may not be noticed if there are slight obstructions in an individual's visual field. Previously, it has been stated that humans hold a very good internal representation of visual stimuli. Studies involving mudsplashes have shown that change blindness may occur because our internal representations of visual stimuli may be much worse than previous studies have shown.[12] Mudsplashes have not been used as frequently as the flicker or forced choice detection paradigms in change blindness research, but have yielded many significant and groundbreaking results.

The foreground-background segregation method for studying change blindness uses photographs of scenery with a distinct foreground and background. Researchers using this paradigm have found that individuals are usually able to recognize relatively small changes in the foreground of an image.[23] In addition, large changes to the colour of the background take significantly longer to detect.[23] This paradigm is critical to change blindness research because many previous studies have not examined the location of changes in the visual field.

Various studies have used MRIs (Magnetic Resonance Imaging) to measure brain activity when individuals detect (or fail to detect) a change in the environment. When individuals detect a change, the neural networks of the parietal and right dorsolateral prefrontal lobe regions are strongly activated.[24][25] If individuals were instructed to detect changes in faces, the fusiform face area was also significantly activated. In addition, other structures such as the pulvinar, cerebellum, and inferior temporal gyrus also showed an increase in activation when individuals reported a change.[25] It has been proposed that the parietal and frontal cortex along with the cerebellum and pulvinar might be used to direct an organisms attention to a change in the environment. A decrease of activation in these brain areas was observed if a change was not detected by the organism.[24] Furthermore, the neurological activation of these highlighted brain areas was correlated with an individuals conscious awareness of change and not the physical change itself.[25]

Other studies using fMRI (Functional Magnetic Resonance Imaging) scanners have shown that when change is not consciously detected, there was a significant decrease in the dorsolateral prefrontal and parietal lobe regions.[24] These results further the importance of the dorsolateral prefrontal and parietal cortext in the detection of visual change. In addition to fMRI studies, recent research has used transcranial magnetic stimulation (TMS) in order to inhibit areas of the brain while participants were instructed to try to detect the change between two images.[26] The results show that when the posterior parietal cortex (PPC) is inhibited, individuals are significantly slower at detecting change.[26] The PPC is critical for encoding and maintaining visual images in short term working memory, which demonstrates the importance of the PPC in terms of detecting changes between images.[26] For a change to be detected, the information of the first picture needs to be held in working memory and compared to the second picture. If the PPC is inhibited, the area of the brain responsible for encoding visual images will not function properly. The information will not be encoded and will not be held in working memory and compared to the second picture, thus inducing change blindness.

The role of attention is critical for an organisms ability to detect change. In order for an organism to detect change, visual stimulation must enter through eye and proceed through the visual stream in the brain. A study in 2004 demonstrated that if the superior colliculus (responsible for eye movements) of a monkeys brain is electrically stimulated, there would be a significant decrease in reaction time to detect the change.[27] Therefore, it is critical for organisms to attend to the change in order for it to be detected. Organisms are only able to detect this change once the visual stimulation comes through the eye (its movements are controlled by the superior colliculus) and is subsequently processed through the visual stream.

Age has been implicated as one of the factors which modulates the severity of change blindness. In a study conducted by Veiel et al. it was found that older individuals were slower to detect the changes in a change blindness experiment than were younger individuals.[28] This trend was also noticed by Caird et al., who found that drivers aged 65 and older were more prone to making incorrect decisions after a change blindness paradigm was used at an intersection, than were participants aged 1864.[29]

Attention is another factor that has been implicated in change blindness. Increasing shifts in attention decrease the severity of change blindness[30] and changes in the foreground are detected more readily than changes made to the background of an image, an effect of the intentional bias for foreground elements.[31]

Object presentation is the way in which objects appear and is a factor that determines the occurrence of change blindness. Change blindness can occur even without a delay between the original image and the altered image, but only if the change in the image forces the viewer to redefine the objects in the image.[32] Additionally, the appearance of a new object is more resistant to change blindness than a looming object, and both the appearance of a new object and the looming of an object are more resistant to change blindness than the receding of an object.[33] Furthermore, the appearance or onset of an object is more resistant to the occurrence of change blindness than the disappearance or offset of an object.[34]

Substance use has been found to affect the detection biases on change detection tasks. If an individual was presented with two changes simultaneously, those that had a change related to the substance they use regularly reported using the substance more than those detecting the neutral stimuli. This indicates a relationship between substance use and change detection within a change blindness paradigm.[35] This bias for devoting more attention to the drug-relevant stimuli is also observed with problem drinkers. Individuals who have a more severe drinking problem are quicker to detect changes in alcohol-related stimuli than in neutral stimuli.[36]

In addition to change blindness induced by changes in visual images, change blindness also exists for the other senses:

The phenomenon of change blindness has practical implications in the following areas:

Research in change blindness has uncovered the possibility of inaccuracy in eyewitness testimony.[39] In many cases, witnesses are rarely able to detect a change in the criminal's identity unless first intending to remember the incident in question.[39] This inability to detect a change in identity can lead to inaccuracy in identifying criminals, mistaken eyewitness identification, and wrongful conviction.[40] Therefore, eyewitness testimonies should be handled with caution in court in order to avoid any of these negative consequences.[40]

Older drivers make more incorrect decisions than younger drivers when faced with a change in the scene at an intersection.[29] This can be attributed to the fact that older individuals notice change at a slower rate compared to younger individuals.[29] In addition, the location and relevance of changes have an effect on what is noticed while driving.[41] The reaction time to changes in the driver's peripherals is much slower than the reaction time to changes that occur towards the center of the driver's visual field.[41] Furthermore, drivers are also able to recognize more relevant changes as opposed to irrelevant ones.[41] Research on the effects of change blindness while driving could provide insight into potential explanations of why car accidents occur.

Military command and control personnel who monitor multiple displays have a delayed time to accurately identify changes due to the necessity of verifying the changes, as well as the effective 'guessing' on some trials.[42] Due to the fact that control personnel have delayed reaction because of change blindness, an interface design of computer work stations may be extremely beneficial to improve the reaction time and accuracy.[42]

Change blindness blindness is defined as a misplaced confidence in ones ability to correctly identify visual changes.[43] People are fairly confident in their ability to detect a change, but most people exhibit poor performance on a change blindness task.

The spotlight effect is a social phenomenon that is defined as an overestimation of the ability of others to notice us.[45] A seemingly obvious change such as another individual changing a sweater during a memory task is rarely noticed.[45] However, the individuals switching the sweater tend to overestimate the ability of the test writers to notice the change in sweaters.[45] In the spotlight effect, this poor performance is a result of the overestimation of others ability to notice us whereas in change blindness blindness it is the overestimation of others ability to notice the sweater change. In other words, it is the distinction between noticing differences on a person and noticing differences between any images.

Read the original:
Change blindness - Wikipedia, the free encyclopedia

Have you ever put on a blindfold and pretended that you couldn't see? You probably bumped into things and got confused about which way you were going. But if you had to, you could get adjusted and learn to live without your sight.

Lots of people have done just that. They have found ways to learn, play, and work, even though they have trouble seeing or can't see at all.

Your eyes and your brain work together to see. The eye is made up of many different parts, including the cornea, iris, lens, and retina. These parts all work together to focus on light and images. Your eyes then use special nerves to send what you see to your brain, so your brain can process and recognize what you're seeing. In eyes that work correctly, this process happens almost instantly.

When this doesn't work the way it should, a person may be visually impaired, or blind. The problem may affect one eye or both eyes.

When you think of being blind, you might imagine total darkness. But most people who are blind can still see a little light or shadows. They just can't see things clearly. People who have some sight, but still need a lot of help, are sometimes called "legally blind."

Vision problems can develop before a baby is born. Sometimes, parts of the eyes don't form the way they should. A kid's eyes might look fine, but the brain has trouble processing the information they send. The optic nerve sends pictures to the brain, so if the nerve doesn't form correctly, the baby's brain won't receive the messages needed for sight.

Blindness can be genetic (or inherited), which means that this problem gets passed down to a kid from parents through genes.

Blindness also can be caused by an accident, if something hurts the eye. That's why it's so important to protect your eyes when you play certain sports, such as hockey.

Some illnesses, such as diabetes, can damage a person's vision over time. Other eye diseases, such as cataracts (say: KAH-tuh-rakts), can cause vision problems or blindness, but they usually affect older people.

Read the original here:
Blindness - Kids Health:

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Julian Assange: Why the world needs WikiLeaks

Gayla Benefield was just doing her job until she uncovered an awful secret about her hometown that meant its mortality rate was 80 times higher than anywhere else in the U.S. But when she tried to tell people about it, she learned an even more shocking truth: People didnt want to know. In a talk thats part history lesson, part call-to-action, Margaret Heffernan demonstrates the danger of "willful blindness" and praises ordinary people like Benefield who are willing to speak up. (Filmed at TEDxDanubia.)

This talk was presented to a local audience at TEDxDanubia, an independent event. TED editors featured it among our selections on the home page.

How willful blindness can corrupt the workplace

In a half-hour podcast from BBC Radio 4, Margaret Heffernan explores how we choose to be ignorant in big businesses and how this can have serious consequences.

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Margaret Heffernan: The dangers of "willful blindness ...

Blindness is the inability to see anything, even light. If youre partially blind, you have limited vision. For example, you may have blurry vision or the inability to distinguish the shapes of objects. Complete blindness means that you cant see at all and are in total darkness. Legal blindness refers to vision thats highly compromised. What a person with healthy eyes can see from 200 feet away a legally blind person can see only from 20 feet away.

Seek medical attention right away if you suddenly lose the ability to see. Have someone bring you to the emergency room for treatment. Dont wait for your vision to return. Depending on the cause of your blindness, immediate treatment may increase your chances of restoring your vision. Treatment may involve surgery or medication.

If youre completely blind, you can see nothing. If youre partially blind, you might experience the following symptoms:

Your childs visual system begins to develop in the womb, but it wont be fully formed until about 2 years of age. By 6 to 8 weeks of age, your baby should be able to fix their gaze on an object and follow its movement. By 4 months of age, their eyes should be properly aligned and not turned inward or outward.

The symptoms of visual impairment in young children can include:

The following eye diseases and conditions can cause blindness:

Blindness is a potential complication if you have diabetes or have a stroke. Birth defects, eye injuries, and complications from eye surgery are other common causes of blindness.

The following conditions can impair vision or cause blindness in infants:

The following categories of people are at risk of blindness:

A thorough eye exam by an optometrist will help to determine the cause of your blindness or partial loss of vision. Your eye doctor will administer a series of tests that measure the clarity of your vision, the function of your eye muscles, and how your pupils react to light. Theyll examine the general health of your eyes using a slit lamp, which is a low-power microscope paired with a high-intensity light.

A pediatrician will screen your baby for eye problems shortly after birth. At 6 months of age, you should have an eye doctor or pediatrician check your child again for visual acuity, focus, and eye alignment. The doctor will look at your babys eye structures and see whether they can follow a light or colorful object with their eyes.

Your child should be able to pay attention to visual stimuli by 6 to 8 weeks of age. If your child doesnt react to light shining in their eyes or focus on colorful objects by 2 to 3 months of age, have their eyes examined right away. You should have their eyes examined if you notice crossed eyes or any other symptoms of impaired vision.

In some cases of vision impairment, one or more of the following may help to restore your vision:

If you experience partial blindness that cant be corrected, your doctor will provide guidance on how to function with limited vision. For example, you can use a magnifying glass to read, increase the text size on your computer, and use audio clocks and audiobooks.

Complete blindness requires approaching life in a new way and learning new skills. For example, you may need to learn how to:

You may also need to have handrails installed in your bathroom.

The long-term outlook for restoring vision and slowing vision loss is better when treatment is preventive and sought immediately. Cataracts can be treated effectively with surgery and dont necessarily result in blindness. Early diagnosis and treatment are also important in cases of glaucoma and macular degeneration to help slow down or stop your vision loss.

To detect eye diseases and help prevent vision loss, get regular eye examinations. If youre diagnosed with certain eye conditions, such as glaucoma, treatment with medication can help prevent blindness.

Have your childs eyes examined at 6 months of age, 3 years of age, and every two years between the ages of 6 and 18 years old to help prevent vision loss. If you notice symptoms of vision loss between routine visits, make an appointment with their eye doctor immediately.

Written by: Chitra Badii and Marijane Leonard Published on: Jul 25, 2012 Medically reviewed on: Mar 09, 2016: [Ljava.lang.Object;@691aed25

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Health Article - What causes blindness? 23 possible ...

In the UK, there are almost 2 million people living with sight loss. Of these, around 360,000 are registered as blind or partially sighted.

Being toldyouhave a visual impairment that can't be treated can be difficult to come to terms with. Somepeople go through a process similar to bereavement, where they experience a range of emotions including shock, anger, and denial, before eventually coming to accept their condition.

If you're blind or partially sighted, you may be referred to a specialist low-vision clinic, which is often located within a hospital. Staff at the clinic can help you understand your condition and come to termswith your diagnosis. They can also advise you about practical things, such as lighting and vision aids, and let you know about further sources of help and support.

Ask your local hospital if they have an Eye Clinic Liaison Officer (ECLO), whose role involves providing support to people with vision loss in eye clinics.

If you're blind or partially sighted, you may find it helpfulto contact a support group for people with visionloss.

TheRoyal National Institute of Blind People (RNIB)is the UKs leading charity for people with vision loss, and it has a useful page on its website about coming to terms with sight loss.

The RNIB's helpline is open Monday to Friday from 8.45am to 5.30pm. The number is 0303 123 9999, with calls costing no more than a standard rate call to an 01 or 02 number. You can alsoemail helpline staff (helpline@rnib.org.uk).

The RNIB's website is specially designed for people with sight loss and provides a wide range of useful information and resources, including an online community andonline shop.

Action for Blind Peopleis another national charity that provides blind and partially sighted people with practical help and support.

For example, the charity can provide you withsupport and information about the day-to-day practicalities of living with a visual impairment, such as adjusting your home to make it easier to get around.

Other national charities that specialise in vision loss and you may find useful include:

There are also many local voluntary organisations around the country that help and support people with vision problems. You can search by postcode on a website called Visionaryto find local support organisations near you.

If your vision has deteriorated to a certain level, you may choose to register as visually impaired. Depending on the severity of your vision loss you'll either be registered as sight impaired (previously"partially sighted") or severely sight impaired (previously "blind").

Your eye specialist (ophthalmologist) will measure your visual acuity (ability to see detail at a distance) and your field of vision (how much you can see from the side of your eye when looking straight ahead).

These measurements will help yourophthalmologist determine whether youre eligible to be certified as sight impairedor severely sight impaired. If you are,they will complete an official certificate with the results of your eye examination.

In England and Wales this certificate is called the Certificate of Vision Impairment (CVI), in Scotland its called BP1, and in Northern Ireland its called A655.

Your ophthalmologist will send a copyof the certificate to you, a copy to your GP and a copy toyour local social services department. Upon receiving the certificate,your local social services team will contact you to ask whether you want to be added toits register of visually impaired people.

After you're registered, social services will contact you again toarrange for an assessment to be carried out. The aim is to assess your needs and find out what help you require to remain independent, such as help with cleaning and cooking, or help with mobility and transport.

Registering as visually impaired isn't compulsory, but it canentitle you to a range of benefits including:

The RNIB website has more information about registering your sight loss. You can also read more aboutregistering vision impairmenton GOV.UK.

Most visually impaired people can continue to live at home. However, you'llprobably need to makesome changes to your home, particularly if you live on your own.

Below is a list of someimportant pieces of equipment you may find useful.

The way your house is painted can also make it easier to find your way around. Using a two-tone contrast approach, such as black and white, can make it easier to tell the difference between nearby objects, such as a door and its handle or the stairs and its handrail.

There are several options available if you're having problems reading standard text in books, newspapers and magazines.

One of the simplest options is to usea magnifying device that can make print appear bigger to help you read. These can be obtained from a number of places including hospital low vision services, optometrists, local voluntary organisations, and the RNIB.

The RNIB also has a collection of large print publications you can borrow, as do most libraries.

You could alsouse an e-reader to help you read.E-readers are handheld devices that allow you to download books and subscribe to newspapers and magazines on the internet. You can choose a setting that allows you to display text at a larger size.

If you're unable to read at all you could sign up to the:

You can also install screen-reading software on your computer that will read out emails, documents and text on the internet.

A charity called Communication for Blind and Disabled People has released a free screen reader for the PC called Thunder. Similar software is available for Apple devices, although you may have to pay a small fee.

There are also voice recognition programmes where you speak into a microphone and the software translates what you say into writing. These programmes can also be usedto issue commands, such as closing down the internet and moving from one website to another.

Some people with severe sight loss, particularly those who've had the problem from a young age,choose to learn Braille. Braille is a writing system where raised dots are used as a substitute for written letters.

As well as Braille versions of books and magazines, you can buy Braille display units, which can be attached to computers that allow you to read the text displayed ona computer screen. Braille computer keyboards are also available.

The RNIB website has more information aboutreading and Braille.

There are several different methods you can use toget around independentlyif you have a problem with your vision.

You may find a long cane useful when travelling. These type ofcanes are usually foldable andcan help you get around by detecting objects in your path. The cane will also make drivers and other pedestrians aware that you have sight loss.

To get the most from a longcane,it's a good ideato attend a training course that will teach you how to use it. The RNIB or Guide Dogs canprovide you with further details about training.

The charityGuide Dogs has been providing guide dogsfor people with vision lossfor many years. Guide dogs can help you get around, and provide both a sense of independence and companionship.

If you apply for a guide dog, Guide Dogs provide all the essential equipment free of charge and can also offer financial assistance if needed for things like food or vet costs.

You don't need to have lost all your sight to benefit from a guide dog and you don't have to be officially registered as blind or partially-sighted to apply for one. The Guide Dogs website has more information about applying for a guide dog.

Guide Dogs alsooffer a number ofother servicesfor people with a visual impairment (even if you don't have a guide dog), such asChildren and Young People's Servicesand mobility training.

The charityalso providesthe My Guide service, whichaims to reduce the isolation that many people with sight loss experience, helping to rebuild their confidence and regain their independence.

A global positioning system (GPS) is a navigational aid that uses signals from satellites to tell you where you are and help plan your journeys.

GPS devices are available as stand-alone units that can be programmed using a Braille keyboard, which tell you your current location and give you directions to where you want to go.

If you have a smartphone, there are a number of GPS apps you can download.

The RNIB website has more information abouttechnology and products for people with sight loss, includingGPS.

If you're diagnosed with a condition that affects your vision, you have a legal obligation to inform the Driver and Vehicle Licensing Agency (DVLA). Failure to do so is a crime and can result in a fine of up to 1,000.

Visit GOV.UK for more information aboutdriving with a disability or a health condition.

If you're registered as having a sight impairment, the DVLA will assume your driving licence is no longer valid and you'll no longer be able to drive.

Exceptions are occasionally made for people with mildvision impairment. If you think this applies to you, then your doctor will need to fill in a DVLA medical information questionnaire (PDF, 265kb).

You're only legally allowed to drive if you can read a number plate from a distance of 20 metres (65 feet), and an eyetest shows your visual acuity is at least 6/12. You're allowed to wear glasses or contact lenses when reading the plate or letter chart.

There are also standards relating to your visual field and driving. If you have a condition that mayreduce your visual field, the DVLA may ask you to completea visual field test to demonstrate you're safe to drive.

If you're currently employed and have recently been diagnosed with a visual impairment, you should contact theAccess to Work scheme.

Access to Work is a scheme run by Jobcentre Plus that provides advice and support about what equipment and adjustments may be required to enable you to do your job.

They also offer a grant to contribute towards the costs of any equipment or training you may need, such as voice recognition software, a Braille keyboard and display unit and a printer that can convert text into Braille (Braille embossers).

Depending on the size of the company you work for, the grant can pay for 80-100% of costs, up to 10,000.

If you're currently looking for work, there are three main organisations that can provide extra advice and support:

You don't have to disclose that you have a visual impairment when applying for a job, but it'susually recommended that you do.

If you feel you've been turned down for a job because of your disability, and you were capable of doing the job, you can make a complaint under the Equality Act 2010.

Some people with a visual impairment decide to become self-employed, often because it allows them the flexibility to work at home for hours they choose.

Action for Blind People has self-employment advisers who can provide information and training on issues such as drawing up a business plan, obtaining funding and book-keeping.

The RNIB website hasmore information and advice aboutwork and employment. You can also read more about employmenton the Action for Blind People website.

If you havevision loss, it's still important to have regular sighttests so your optometrist (eye specialist) can check for further changes in your eyes and give you advice about how to make thebest use of your vision.

Find an optician near youandread more aboutNHS eye care services.

Page last reviewed: 08/07/2015

Next review due: 08/07/2017

More here:
Blindness and vision loss - NHS Choices

Blindness (Portuguese: Ensaio sobre a cegueira, meaning Essay on Blindness) is a novel by Portuguese author Jos Saramago. It is one of his most famous novels, along with The Gospel According to Jesus Christ and Baltasar and Blimunda.

Blindness is the story of an unexplained mass epidemic of blindness afflicting nearly everyone in an unnamed city, and the social breakdown that swiftly follows. The novel follows the misfortunes of a handful of characters who are among the first to be stricken and centers on "the doctor's wife," her husband, several of his patients, and assorted others, thrown together by chance. After lengthy and traumatic quarantine in an asylum, the group bands together in a family-like unit to survive by their wits and by the unexplained good fortune that the doctors wife has escaped the blindness. The sudden onset and unexplained origin and nature of the blindness cause widespread panic, and the social order rapidly unravels as the government attempts to contain the apparent contagion and keep order via increasingly repressive and inept measures.

The first part of the novel follows the experiences of the central characters in the filthy, overcrowded asylum where they and other blind people have been quarantined. Hygiene, living conditions, and morale degrade horrifically in a very short period, mirroring the society outside.

Anxiety over the availability of food, caused by delivery irregularities, acts to undermine solidarity; and lack of organization prevents the internees from fairly distributing food or chores. Soldiers assigned to guard the asylum and look after the well-being of the internees become increasingly antipathetic as one soldier after another becomes infected. The military refuse to allow in basic medicines, so that a simple infection becomes deadly. Fearing a break out, soldiers shoot down a crowd of internees waiting upon food delivery.

Conditions degenerate further, as an armed clique gains control over food deliveries, subjugating their fellow internees and exposing them to rape and deprivation. Faced with starvation, internees do battle and burn down the asylum, only to find that the army has abandoned the asylum, after which the protagonists join the throngs of nearly helpless blind people outside who wander the devastated city and fight one another to survive.

The story then follows the doctor's wife, her husband, and their impromptu family as they attempt to survive outside, cared for largely by the doctors wife, who can still see (though she must hide this fact at first). The breakdown of society is near total. Law and order, social services, government, schools, etc., no longer function. Families have been separated and cannot find each other. People squat in abandoned buildings and scrounge for food. Violence, disease, and despair threaten to overwhelm human coping. The doctor and his wife and their new family eventually make a permanent home in the doctor's house and are establishing a new order to their lives when the blindness lifts from the city en masse just as suddenly and inexplicably as it struck.

The doctor's wife is the only character in the entire novel who does not lose their sight. This phenomenon remains unexplained in the novel. Unable to leave her husband to be interned, she lies to the doctors and claims to be blind. At this point she is interned with the rest of the afflicted. Once inside, she attempts to help the compound organize, but she is increasingly unable to hold back the animality of the compound. When one ward begins withholding food and demanding that the women of other wards sleep with them to be fed, she kills the leader of their ward. Once they escape the compound, she helps her group survive in the city. The doctor's wife is the de facto leader of their small group, although in the end she often serves their disabled needs.[1]

The doctor is an ophthalmologist stricken blind after treating a patient with what will come to be called "the white sickness,"He is among the first to be quarantined along with his wife. Due to his medical expertise he has a certain authority among those quarantined. Several of the other main characters had been visiting the doctor's office when the epidemic begins to spread. Much of this really comes from his wife not having gone blind; she is able to see what is going on on the ward and relay this to her husband. When the group from his ward finally escapes they end up travelling to and staying in the doctor and his wife's apartment. [1]

The girl with the dark glasses is a former part-time prostitute who is struck blind while with a customer. She is unceremoniously removed from the hotel and taken to the quarantine. Once inside, she joins the small group of people who were contaminated at the doctor's office. When the car thief gropes her on the way to the lavatory, she kicks him giving him a wound from which he will eventually die. While inside, she also takes care of the boy with the squint, whose mother is nowhere to be found. At the end of the story, she and the old man with the black eye patch become lovers.[1]

The old man with the black eye patch is the last person to join the first ward. He brings with him a portable transistor radio that allows the internees to listen to the news. He is also the main architect of the failed attack on the ward of hoodlums hoarding the food rations. Once the group escapes the quarantine, the old man becomes the lover of the girl with the dark glasses.[1]

The dog of tears is a dog that joins the small group of blind when they leave the quarantine. While he mostly loyal to the doctor's wife, he helps the whole group by protecting them all from packs of dogs who are becoming more feral by the day. He is called the dog of tears because he becomes attached to the group when he licks the tears off the face of the doctor's wife.[1]

The boy with the squint was a patient of the doctor's, which is most likely how he became infected. He is brought to the quarantine without his mother and soon falls in with the group in the first ward. The girl with the dark glasses feeds him and takes care of him like a mother.[1]

After the first blind man was struck blind in traffic, a car thief brought him home and, subsequently stole his car. Soon after he went blind, the car thief and the first blind man reencounter one another in the quarantine, where they soon come to blows. They have no time to resolve their issues, though, since the car thief is the first internee killed by the guards. He is gunned down while trying to ask the guards for medication for his infected leg.[1]

The first man to go blind is struck blind in the middle of traffic, waiting at a stoplight. He is immediately taken home and then to the doctor's office, where he infects all of the other patients. He is one of the principle members of the first ward - the ward with all of the original internees. He is also the first to regain his sight, when the epidemic is finally over.[1]

The wife of the first blind man goes blind soon after helping her husband to the quarantine. They are reunited by pure chance in the quarantine. Once inside, she also joins the first ward with the doctor and the doctor's wife. When the ward of hoodlums begins to demand that the women sleep with them in order to be fed, the first blind man's wife volunteers to go, in solidarity with the others.[1]

The man with the gun is the leader of the ward of hoodlums that seizes control of the food supply in the quarantine. He and his ward take the rations by force and threaten to shoot anyone who doesn't comply. This ward extorts valuables from the other internees in exchange for food and, when the bracelets and watches run out, they begin to rape the women. He is later stabbed to death by the doctor's wife.[1]

This man is not one of those afflicted by the "white sickness"rather he has been blind since birth. He is the only one in the ward who can read and write braille and who knows how to use a walking stick. Additionally, he is the second in command to the man with the gun in the ward of hoodlums. When the doctor's wife kills the man with the gun, the blind accountant takes the gun and tries to seize control but he is unable to rally support. He dies when one of the rape victims sets fire to the ward.[1]

Like most works by Saramago, the novel contains many long, breathless sentences in which commas take the place of periods. The lack of quotation marks around dialogue means that the speakers' identities (or the fact that dialogue is occurring) may not be immediately apparent to the reader. The lack of proper character names in Blindness is typical of many of Saramago's novels (e.g. All the Names). The characters are instead referred to by descriptive appellations such as "the doctor's wife", "the car thief", or "the first blind man". Given the characters' blindness, some of these names seem ironic ("the boy with the squint" or "the girl with the dark glasses").

The city afflicted by the blindness is never named, nor the country specified. Few definite identifiers of culture are given, which contributes an element of timelessness and universality to the novel. Some signs hint that the country is Saramago's homeland of Portugal: the main character is shown eating chourio, a spicy sausage, and some dialogue in the original Portuguese employs the familiar "tu" second-person singular verb form (a distinction which used to exist in English as the now largely archaic pronoun thou). The church, with all its saintly images, is likely of the Catholic variety.

Saramago wrote a sequel to Blindness in 2004, titled Seeing (Ensaio sobre a lucidez, literal English translation Essay on lucidity), which has also been translated into English. The new novel takes place in Portugal and features several of the same characters.

An English-language film adaptation of Blindness was directed by Fernando Meirelles. Filming began in July 2007 and stars Mark Ruffalo as the doctor and Julianne Moore as the doctor's wife. The film opened the 2008 Cannes Film Festival.[2]

In 2007 the Drama Desk Award Winning Godlight Theatre Company[3] staged the New York City theatrical premiere of Blindness [4] at 59E59 Theaters. This stage version was adapted and directed by Joe Tantalo. The First Blind Man was played by Mike Roche.[4]

An outdoor performance adaptation by the Polish group Teatr KTO, was first presented in June 2010. It has since been performed at a number of venues, including the Old College Quad of Edinburgh University during the 2012 Edinburgh Festival Fringe.

Shortly before his death, Saramago gave German composer Anno Schreier the rights to compose an opera based on the novel. The libretto is written in German by Kerstin Maria Phler. Like the German translation of the novel, the opera's title is "Die Stadt der Blinden". It saw its first performance on November 12, 2011 at the Zurich Opera House.

Read more:
Blindness (novel) - Wikipedia, the free encyclopedia

The Scripps Research Institute (TSRI) undertakes basic biomedical research, primarily in laboratory settings, to learn how the human body operates on all levels. Our discoveries are often licensed to biotechnology or pharmaceutical firms for further development toward a drug or treatment. As a nonprofit biomedical research institute we do not see patients and rarely conduct clinical trials; for the latest information on clinical trials throughout the United States, visit http://www.clinicaltrials.gov . For information on specific diseases, search for associations or organizations dedicated to the disease, for example, the National Eye Institute or the American Foundation for the Blind.

Vision loss is most accurately described in terms of a range of function, from the ability to see relatively clearly to diminishing eyesight levels and total blindness. The World Health Organization (WHO) specifies four levels of visual function: normal, moderate visual impairment, severe visual impairment, and blindness.

With moderate to severe vision impairment, a persons eyesight cannot be corrected to a normal level, even with eyeglasses, contact lenses, medicine, or surgery. As described by the U.S. Centers for Disease Control, such impairment can be distinguished by a loss of visual acuity, where the eye does not see objects as clearly as usual, or a loss of visual field, where the eye cannot see as wide an area as usual without moving the eyes or turning the head. In the United States, legal blindness is defined as a visual acuity of 20/200 (normally 20/20) or worse with the best possible correction, or a visual field of 20 degrees (normally 160 to 170 degrees) or less.

The latest WHO figures state about 314 million people worldwide are visually impaired; 45 million are blind. Common causes of vision loss and blindness include:* Cataract (a clouding of the eye lens that hinders passage of light)* Uncorrected refractive errors (near-sightedness, far-sightedness, astigmatism (abnormal curvature of the cornea), or presbyopia (a focusing problem that makes it difficult to see near objects))* Glaucoma (a slow build-up of fluids in the eye producing excessive pressure that damages the optic nerve)* Macular degeneration (a breakdown of the retina, which involves loss of the central field of vision)* Diabetic retinopathy (changes in the blood vessels of the light-sensitive retina tissue in the back of the eye)* Retinitis pigmentosa (a hereditary, progressive loss of vision, often beginning with night blindness, with narrowing visual field leading to tunnel vision and, frequently, total blindness)

Other causes of blindness include stroke, accidents or injury to the eye, blocked blood vessels, optic neuritis, tumors, complications of premature birth, vitamin A deficiency in children, and infections.

Age is a common factor in vision loss. In the United States, according to the National Institutes of Health (NIH), irreversible vision loss is most prevalent among people aged 65 and older. A 2007 NIH/Blindness Prevention America report states blindness affects more than one million Americans aged 40 and older. The visually impaired, including those who are blind, total more than 3.6 million older Americans. According to the report, the prevalence of blindness and vision impairment increases rapidly in the later years, particularly after age 75.

WHO refers to studies that indicate women have a significantly higher risk of visual impairment than men, in every region of the world and at all ages.

About three-fourths of all visual impairment globally is preventable, according to WHO. Early detection, diagnosis, and treatment can help alleviate or forestall increased loss of vision. For example, timely correction can help prevent severe vision impairment in individuals with eyesight impaired by refractive errors. In addition, treatment of diabetes through diet, exercise, careful control of blood-sugar levels, and avoidance of smoking can help prevent blindness from diabetic retinopathy. Recommending regular comprehensive eye exams, the NIH advises being alert to subtle, small changes in vision, e.g., difficulty in focusing on near or distant objects, unusual sensitivity to light or glare, squinting, or inability to recognize familiar faces.

More here:
Discover - Blindness and Vision Loss Research

We at the Foundation Fighting Blindness have been receiving questions about acupuncture for the treatment of retinitis pigmentosa (RP), namely because of feasibility research conducted by Ava Bittner, O.D., Ph.D., at Johns Hopkins University, in collaboration with Andy Rosenfarb, N.D., L.Ac, who specializes in acupuncture and ophthalmic Chinese medicine. Their project was funded by the National Institutes of Health (NIH).

Cutting to the chase, that study did not provide us with enough information to know if acupuncture can save or restore vision in people with RP. I will, in a moment, report on what we have learned thus far, as well as on the design of Dr. Bittners forthcoming acupuncture study, which will hopefully tell us more.

But I have one important comment before I discuss the research: I strongly recommend that people affected by RP and other retinal diseases hold off on trying acupuncture therapy for their retinal conditions until more is known about its risks and benefits. While Dr. Rosenfarb has used acupuncture to treat people with RP in his clinical practice, his approach has not yet been formally studied in a randomized, controlled clinical trial.

Furthermore, Dr. Bittner informed us that acupuncture needles, if not properly administered by an acupuncturist trained in specific needling techniques for treating RP, can potentially cause nerve damage, infection and other problems. So, there are real risks if the therapy is administered by someone who does not have the appropriate skill and expertise, especially given that Dr. Rosenfarbs protocol involves administration around (not in!) the eyes. By all means, do not try this at home.

With that important disclaimer out of the way, let me tell you what we know about acupuncture. First, it is being widely used and studied by the Western medical community, especially for the treatment of chronic pain and discomfort related to a variety of diseases and conditions. Also, I recently compiled a list of about 60 acupuncture studies that are currently funded by the NIH. So, acupuncture definitely has additional potential benefits, and the breadth of those is being aggressively explored.

Second, we have evidence from a 2006 lab study that electroacupuncture in which a low-intensity electrical current is passed through needles might be therapeutic for retinal degenerations. An Italian research team led by Dr. Lucia Pagani showed that electroacupuncture released neurotrophic (i.e., protective) proteins in the retinas of rats with retinal degeneration. While vision in the rats was not measured, treated rats had thicker and healthier retinas than those that were untreated.

Last, we have Dr. Bittners recently completed 12-person feasibility study of electroacupuncture for people with RP. Results of the research were published in the journal Clinical and Experimental Optometry. In the study, participants received 10 half-hour treatments over a two-week period from Johns Hopkins acupuncturist Jeff Gould, who was trained by Dr. Rosenfarb to administer a standardized protocol designed specifically for the RP trial.

Dr. Bittner reported that eight of those participants had significant vision improvements in night vision, dark adaptation and/or visual field. She followed three of those patients for approximately a year, and their night-vision improvements were sustained. She continues to follow those three individuals to see how their night vision changes over time.

Later this year, Dr. Bittner will launch a one-year, 21-person study of electroacupuncture funded by the National Eye Institute. In this research effort, she and her colleagues will compare a control group to two therapeutic approaches: electroacupuncture and transcorneal stimulation, which involves sending a small electrical current through a wire placed on the surface of the eye.

Transcorneal stimulation has had encouraging results (increases in visual field) in small-scale German clinical trials. Dr. Bittner and her colleagues will also look at additional parameters of retinal health and vision improvement, including retinal blood flow and retinal sensitivity as measured by an electroretinogram.

Even after the small-scale, one-year study is completed, there will still be much that we dont know about acupuncture for retinal degenerations. If there is a benefit, we still wont know which forms of RP will benefit most and/or if acupuncture will save vision in people with other retinal diseases. Additional research will be needed, but I think Dr. Bittner and her colleagues are on the right track to getting the answers. Good research takes time.

If you are interested in participating in Dr. Bittners forthcoming study, send her an email at akiser@jhsph.edu.

Well be sure to report any new findings on acupuncture as we learn about them.

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Is Acupuncture a Beneficial Treatment for Retinitis ...

More color vision deficiency facts and questions...

How does a man/woman affected by CVD perceive this page? Click on: Red/Green or Blue/Yellow color filter (Be patient, the filter activation may take a minute or so...).

What color do color vision deficient people dream in? We only dream of what we know... People who become blind after birth can see colors and images in their dreams. People who are born blind do not see any images, but have dreams equally vivid involving their other senses of sound, smell, touch and emotion. It is hard for a seeing person to imagine it. So, colorblind people dream in the color set they see in real life... However, a full 12% of sighted people dream exclusively in black and white!

Can a color deficient person experience 3D movies or stereoscopic images? It depends on the color vision deficiency, and the degree of severity. A color vision deficient person can see recent 3D movies which are devised to be seen with glasses using crossed polaroid lenses, but not the old style 3D movies devised to be seen wearing anaglyph (red-green) glasses. Redgreen colorblind people do sometimes have difficulties with red-green anaglyph images since although the colors appear similar, the intensities are rather different - the red image typically looks darker than the green.

How do color vision deficient persons perceive a colorwheel?

Reverse color blindness test Color vision deficient people have a tendency to better night vision and, in some situations, they can perceive variations in luminosity that color-sighted people could not. In fact, most color blind people can easily read what is written in the picture below... That means, if you fail the test, you probably have the full range of color sensitivity that is attributed to color-sighted people. Anyway, this test is not to be considered by itself sufficient to determinate defective color vision. (Highlight answer: NO)

Image taken from Sarcone's book Puzzillusions

What bothers colorblind people most? - When grilling a piece of meat, a red deficient individual cannot tell whether it is raw or well done. Many cannot tell the difference between green and ripe tomatoes or between ketchup and chocolate syrup! Many others are always buying and biting into unripe bananas - they cannot tell if they are yellow or green, and the matt, natural material makes it even harder to distinguish. - Some food may look definitely disgusting to color vision deficient individuals: a plate full of spinach, for instance, just appears to them like cow pat. - They can however distinguish some citrus fruits. Oranges seem to be of a brighter yellow than that of lemons. - A colorblind person is generally unable to interpret the chemical testing kits for swimming pool water, test strips for hard water, soil or water pH tests because they rely on subtle color differences. - Many colorblind people cannot tell whether a woman is wearing lipstick or not. More difficult to handle for some is the inability to make the difference between a blue-eyed blonde and a green-eyed redhead. - Color vision deficiencies bother affected children from the earliest years. At school, coloring can become a difficulty when one has to take the blue crayon - and not the pink one - to color the ocean. - Bi-color and tri-color LEDs (Light Emitting Diodes): is that glowing indicator light red, yellow, or green? Same problem with the traffic lights... Your personal experiences of being a color blind If you are a color blind person you may want to help us by answering these two questions...

I need to pass a color blindness test for work. What can I do? Some jobs require their employees to take a color vision deficiency test (often using the Ishihara plates above). For instance, good color vision is vital for recognizing various lights and signals important to pilots, especially at night. These tests are required by, among others, the coast-guard and most military and emergency services. Unfortunately, if you really are colorblind, there is very little you can do to pass these tests. However, the CAA UK and the FAA US are currently reviewing the color vision requirements for professional flight crew. Many documents and papers over the last 20 years have stated the need for new color vision tests that are more appropriate to the tasks that pilots carry out. That is the reason why a new range of tests has been developed by Applied Vision Research Centre. For the few subjects that fail or are judged borderline from the results of the first CVD screening test, then a second program will measure the subject's chromatic sensitivity for stimulus conditions that are considered important experimentally. The results from this will then make it possible to judge whether the subject's performance meets the minimum color vision requirements that yield acceptable visual performance in the tasks investigated.

Color blindness cure? No cure exists yet for inherited color deficiency. However, the researchers Jay Neitz and his wife have developed and used gene therapy to restore color vision in two adult male squirrel monkeys that have been unable to distinguish between red and green hues since birth - raising the hope of curing color blindness and other visual disorders in humans. They introduced the human form of the red-detecting opsin gene into a viral vector, and injected the virus behind the retina of the monkeys. The researchers then assessed the monkeys ability to find colored patches of dots on a background of grey dots by training them to touch colored patches on a screen with their heads. After 20 weeks, the monkeys color skills improved dramatically. The insertion of the red-detecting opsin gene gave rise to new color perception stimuli and, in fact, their brain started to react on this new visual information. Gaining this new dimension of color vision becomes a simple (!) matter of splitting the preexisting "blue-yellow" pathway into two systems, one for "blue-yellow" and a second for "red-green" color vision. The Neitzs are still in the middle of clinical trials. Actually, they are not only looking for a cure, but also trying to develop a test that can help forecast the severity of someones color blindness. More info at http://www.neitzvision.com/content/genetherapy.html

How can colorblind people compensate for their deficient color vision? While there are no cures for color blindness, there are many possibilities to help control the annoyance of this disease. A possible treatment for color vision deficiency is to use special glasses with particular color filters to make it easier to interpret colors or actually to better see contrasts. Another way to control symptoms is to use what is called the X-Chrom lens. The X-Chrom lenses are red contact lenses worn on the non-dominant eye of color deficient people and which helps some to better interpret colors or contrasts. The X-Chrom lens does not restore normal color vision, it just allows some colorblind individuals to distinguish colors better.

How can I create a colorblind friendly website? Apart from its aesthetic appeal, seeing many different colors allows us to distinguish things in the world. However, remember that there are always colorblind people among your audience and readers. Actually, there could be more than TEN colorblind people per 250 people visiting your site. Then, we, the web community, must create an atmosphere which makes it easier for colorblind individuals to differentiate between text and background along with images! There are 2 ways that we can make information in pictures available to colorblind people: 1) The simplest way is to increase the red/green contrast in the images. 2) We can also convert the variations in red and green colors into variations in brightness and/or blue/yellow coloration. One way to test your website for colorblind usability is by using these tools: - Colorblind Web Page Filter, - Vischeck. Each tool will show a copy of your web page as if it was seen as a select type of color vision deficiency. Firefox also has a great add-on which allows webmasters to see color contrasts: - Color Contrast Analyser Firefox Extension.

Below is a proposal of a color range selection that may be unambiguous both to color vision deficient people and normal sighted persons. Some useful hints: when combining colors from this pallet, try to use 'warm' and 'cool' colors alternatively. Avoid combination of colors with low saturation or low brightness!

How can teachers help if a student has a color vision deficiency? 1) Always use white chalk, not colored chalk, on the board to maximize contrast. Avoid yellow, orange, or light tan chalk on green chalkboards. 2) Xerox parts of textbooks or any instructional materials printed with colored ink. Black print on red or green paper is not safe. It may appear as black on black to some color vision deficient students.

I am colorblind and work on a computer - is there a way that I can determine the various colored graphics or letters? Yes, there is a new product called Visolve that might help you. It is an interactive software program that takes a picture of your screen and allows you to manipulate various color.

What is the relation between colorectal cancer and color deficiency? Men are statistically more likely to die of colorectal cancer than women, and it is thought that one reason for this is that they are more likely than women to be color vision deficient. The link is that if you are red colorblind, when you look at a piece of used toilet paper it may all look the same color, even though there is red and brown on there. Hopefully, the other symptoms will prompt the color deficient person to seek medical attention (source: h2g2).

Are there 'false' colorblind persons? There is a type of color vision deficiency that is caused by damage to the cerebral cortex of the brain, rather than abnormalities in the cells of the eye's retina. This kind of color vision deficiency is called "cerebral achromatopsia". People affected with cerebral achromatopsia are perfectly aware of their visual experiences; however, they are unable to imagine or remember colors. They see the world like a black & white television where everything is a shade of gray. They cannot chromatically order or discriminate hue but they can distinguish color contrasts like a normal person. 'Transient achromatopsia' is a temporary loss of colour vision caused by a short-lived vascular insufficiency in the occipital cortex.

Are cats and dogs color vision deficient? Yes, we can compare mans best friends vision with the vision of human being suffering from red or green color vision defiency (protanope, deuteranope, see fig. below). Dogs do see in color, but have two-color, or dichromatic vision, that is, they cannot distinguish between red, orange, yellow or green. They can see various shades of blue and can differentiate between closely related shades of grey that are not distinguishable to people.

Cats have the ability to distinguish between blues and greens, but lack the ability to pick out shades of red. They have a wider field of view about 200 degrees, compared with humans' 180-degree view. So, cats have a greater range of peripheral vision. They also are crepuscular, that means they are active at dawn and dusk. Their night vision is far superior to that of humans: cats' eyes have 6 to 8 times more rod cells, which are more sensitive to low light [Images: See What a Cat Sees].

Cats and dogs are primed to see "motion", rather than defining the world through sight alone. They use a blend of senses such as smell and hearing with their vision to do what we humans use our eyes alone to do.

Are goldfish color vision deficient? The common goldfish is not colorblind. It seems that it can see a very wide range of the spectrum both infra-red and ultra-violet and has the largest range so far discovered. In that sense, it is tetrachromatic because its color vision is based on four types of cones (ultraviolet, short, medium and long wavelength-sensitive). Goldfish are actually the only animals that can discriminate, under certain conditions, both infra-red and ultra-violet light. Since they have greater sensitivity to light than we do, it is important then to protect your goldfish from bright lights and sudden movements, and to spend a little time working out the right location for their tank.

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Color Blindness Tests and Facts - Archimedes Laboratory

Title Length Color Rating Use of Blindness in Oedipus the King - Sophocles has been known for using his plays not merely to entertain his audience, but to deliver a message too. Out of all of the important lessons in his plays, Wisdom stands out as the most impact full. After all, "No law or ordinance is mightier than understanding"(Plato 1/2). In the play Oedipus the King, Sophocles uses the blindness of Teriesias, Jocasta, and Oedipus to point out how understanding is far greater than vision alone. In the play Oedipus the King, Sophocles use the blindness of Teiresias to point out the great power behind wisdom and understand.... [tags: Oedipus Rex, Sophocles] :: 5 Works Cited 914 words (2.6 pages) Better Essays [preview] Theme of Blindness in Sophocles' Oedipus the King - Theme of Blindness in Sophocles' Oedipus the King Sophocles?s play, ?Oedipus the King. is one of the most well known of the Greek tragedies. 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[tags: Oedipus the King Oedipus Rex] :: 3 Works Cited 972 words (2.8 pages) Strong Essays [preview] Freud and Sophocles' Oedipus Tyrannus - Were we to temporarily embrace the theories of Freud in our analysis of Oedipus Tyrannus and subsequent plays, we would find ourselves with an incestuous protagonist, so mad in his quest to power that he seeks to kill his father and will stop at nothing to achieve this. It is where Freud misconstrues the very essence of the play that the audience is intended to find its meaning. Were Oedipus aware of his actions throughout the course of the story there would have been no story. Never once was he in the conscious pursuit of his fathers death or mothers marriage bed, and upon hearing of his own actions falls into crippling despair.... [tags: Oedipus Tyrannus] 739 words (2.1 pages) Better Essays [preview] Free Oedipus the King Essays: Metamorphosis of Oedipus - Metamorphosis of Oedipus in Oedipus Rex (the King) The metamorphosis of Oedipus in Sophocles' "Oedipus Rex" is sudden and climactic. Sophocles wrote the tragedy to bring a certain moral conclusion to fruition by the end of the novel. To have change, the character of Oedipus first had to reveal his tragic flaw. He begins the story as a brilliant conqueror and becomes a bereft and blind man at the play's surface. However, the moral of the play is not merely the consequences of attempting to circumvent one's fate.... [tags: Oedipus the King Oedipus Rex] 517 words (1.5 pages) FREE Essays [view] tragoed Oedipus the King (Oedipus Rex) and Greek Tragedy - Oedipus Rex as a Great Greek Tragedy The reader is told in Aristotle's Poetics that tragedy "arouses the emotions of pity and fear, wonder and awe" (The Poetics 10). To Aristotle, the best type of tragedy involves reversal of a situation, recognition from a character, and suffering. The plot has to be complex, and a normal person should fall from prosperity to misfortune due to some type of mistake. Oedipus Rex, by Sophocles, is a great example of a Greek tragedy. Its main plot is Oedipus' goal to find out his true identity, the result being his downfall by finding out he has married his own mother and killed his father.... [tags: Oedipus the King Oedipus Rex] :: 4 Works Cited 1016 words (2.9 pages) Strong Essays [preview] Oedipus the King: Fate and Free Will - Tragedy is an imitation, not of men, but of action and life, of happiness and misery (Milch 12). This statement by Aristotle reflects the ideas portrayed in the play Oedipus Rex. Written by Sophocles, Oedipus Rex is a play which combines tragedy with irony to tell a story of a noble king who falls short of his greatness. The play was written around 430 BC and originally intended for an Athenian audience. They considered Sophocles their most successful playwright and consequently, his works continued to be valued highly throughout the Greek world long after his death.... [tags: Oedipus the King, Oedipus Rex 2014] :: 4 Works Cited 2547 words (7.3 pages) Powerful Essays [preview] Oedipus the King - The Character Transformations of Oedipus - Oedipus the King - The Character Transformations of Oedipus Through the character of Oedipus, Sophocles shows the consequences of defying the divine order. Oedipus served Thebes as a great ruler, loved by his subjects; but, like most in the human race, he slipped through the cracks of perfection. Oedipus had many faults, but it was primarily the tragic flaw of hubris, arrogance from excessive pride, which doomed his existence, regardless of the character attributes that made him such a beloved king.... [tags: Oedipus King Oedipus Rex Essays Papers] :: 5 Works Cited 1236 words (3.5 pages) Strong Essays [preview] The Downfall and Destruction of a King in the Play, Oedipus the King - The Downfall of a King in the Play, Oedipus the King I found the tragedy of "Oedipus the King" to be quite interesting. It was not as hard to read as an epic. "The purpose of tragedy is to arouse the emotions of pity and fear and thus to produce in the audience a catharsis of these emotions." (p488, A Handbook of Literature) A tragedy has more drama and builds to the climax. Oedipus' fate was set into motion by the circumstances he created himself because of his own rashness and arrogance. This is called an inciting incident.... [tags: Oedipus the King Oedipus Rex] 1641 words (4.7 pages) FREE Essays [view] An Intellectual and Emotional Response to Oedipus the King - An Intellectual and Emotional Response to Oedipus the King While reading the play Oedipus the King, my response to the work became more and more clear as the play continued. When I finished the play, my reaction to the work and to two particular characters was startling and very different from my response while I was still reading. My initial response was to the text, and it was mostly an intellectual one. I felt cheated by the play because the challenge of solving the mystery of the plot was spoiled for me by the obvious clues laid out in the work.... [tags: Oedipus the King Oedipus Rex] :: 1 Works Cited 1214 words (3.5 pages) FREE Essays [view] Tragic Flaws in Oedipus the King - Oedipus the King, Sophocles classical Greek tragedy, presents tragic flaw(s) as the cause of the near-total destruction of the life of the protagonist. This essay examines that flaw. In his essay Sophoclean Tragedy Friedrich Nietzsche agrees that there is an error within the protagonist, but refrains from specifying exactly what it is: The most pathetic figure of the Greek theatre, the unfortunate Oedipus, Sophocles takes to be a noble man called to error and alienation in spite of his wisdom, yet called too, in the end, through monstrous suffering, to radiate a magic power rich in a blessing which works even after he passes on.... [tags: Oedipus the King Essays] :: 12 Works Cited 3574 words (10.2 pages) Powerful Essays [preview] Oedipus The King by Sophocles - Oedipus the King by Sophocles is the story of a man who was destined to kill his father and marry his mother. The ancient Greeks believed that their gods decided what would ultimately happen to each and every person.Man was free to choose and was ultimately held responsible for his own actions. Both the concept of fate and free will played an important part in Oedipus' destruction. Although he was a victim of fate, he was not controlled by it. Oedipus was destined from birth to someday marry his mother and to murder his father.... [tags: Oedipus King Sophocles] 1284 words (3.7 pages) FREE Essays [view] The True Vision of Blindness in Oedipus Rex by Sophocles - People may be blinded to truth, and may not realize what truth is, even if truth is standing in front of them. They will never see truth becase they are blind to it. In Oedipus Rex by Sophocles it is easy to see how blindness affects the transition of the story. It is said that blind people see in a different manner because they sense the world in a totally diferent way, such as Teiresias in the play. Oedipus Rex is a tragedy due to the content the Sophocles, the playwright, decided to include, first, murdering his father, king Laius, then marrying his mother, Jocasta, and ending by blinding himself.... [tags: Literary Analysis, Analytical Essay] 973 words (2.8 pages) Strong Essays [preview] Concepts Of Sight in Sophocles Play Oedipus - Concepts Of Sight in Sophocles Play Oedipus The concept of sight is one of the major motifs throughout Sophocles play Oedipus the King. The play revolves primarily around series of events caused by many peoples insight or lack there of. Oedipus does not see that he is caught up in a web of cruel destiny that he cannot escape. The gods demonstrate foresight and insight into the play. In addition to this, Tiresias has physical blindness but also has prophetic insight. Finally, both Oedipus and Jocasta portray types of mental blindness and shortsightedness.... [tags: Sophocles Oedipus King Essays] 1334 words (3.8 pages) Strong Essays [preview] tragoed Free Essay: Oedipus the King (Oedipus Rex) as a Greek Tragedy - Oedipus the King as a Greek Tragedy The Greek tragedy, Oedipus the King, written by Sophocles (496-406 B.C.), adheres to Aristotles (384-322 B.C.) definition of a tragedy. The first criterion of a Greek tragedy is that the protagonist be a good person; doubly blessed with a good heart and noble intention. Sophocles reveals immediately at the start of the play that Oedipus is such a man. As is common in the Greek tragedy Oedipus is also an aristocrat. Born of the King and Queen of Thebes he is of true nobility.... [tags: Oedipus the King Oedipus Rex] 1603 words (4.6 pages) FREE Essays [view] Oedipus And Blindness Imagery - In the story of Oedipus the king, Sophocles beautifully demonstrates the imagery of sight versus blindness through the use of tragedy and ignorance. Oedipus is ignorant to his own incest, therefore causing the first instance of his blindness. The second instance of Oedipus blindness is the ignorance of his true parents identity. The third instance of Oedipus blindness is a literal one, in which he physically blinds himself after finding the body of his mother, or wife. Sophocles utilizes his skill of creating a tragic character by showing Oedipus as blind on multiple levels, all the while being unaware of his blindness until the end.... [tags: essays research papers] 505 words (1.4 pages) Unrated Essays [preview] Dramatic Irony in Sophocles' Oedipus the King - Dramatic Irony in Sophocles' Oedipus the King Oedipus the King is a Greek tragedy written by Sophocles. Sophocles knowing that his audience is aware of the outcome of the play utilizes that knowledge to create various situations in which dramatic irony play key roles. Dramatic irony is when the audience knows the tragic truth before the characters do. Through his use of irony Sophocles manages to avoid retelling an old tale, though the audience is cognizant of the story's end they are intrigued by the irony present in the story. Sophocles made liberal use of irony.... [tags: Oedipus King Oedipus Rex Essays Papers] 967 words (2.8 pages) Strong Essays [preview] Vision and Blindness In Oedipus Tyrannus by Sophocles - The play Oedipus Tyrannus, written by Sophocles, is a play filled with symbols and irony involving the aspect of both vision and blindness. This aspect of the novel takes on an important role in the life of Oedipus, the ruler of Thebes. He originally feels as though he knows and sees everything, nevertheless, as the motto of the Oracle at Delphi states, he does not "know thyself," as he will find out toward the end of the play. The notion of seeing and blindness becomes an important and ironic symbol in the tragic fall of Oedipus, a man who could not escape his lot or moira.... [tags: Oedipus Rex Essays] 670 words (1.9 pages) Unrated Essays [preview] Destiny, Fate, Free Will and Free Choice in Oedipus the King - The Paradox of Free Will - A Paradox: Oedipus's Free will in the Play Oedipus Rex William Shakespeare once wrote, "Who can control his fate?" (Othello, Act v, Sc.2).A hero and leader must acknowledge above all else his honor, and the pride of his image. In ancient Greek beliefs, a hero was a man who stood taller than the rest; he was able to better any conflict. He did this not for himself or for any token award that may be given to him, but for the security of his fellow man. Physical strength and superior wit are the two major characteristics of a hero. These characteristics may be destined; but the use of them to help his fellow man is will. Sophocles's short play Oedipus Rex is a tale of a hero's ascent t... [tags: Oedipus the King Oedipus Rex] 1309 words (3.7 pages) Strong Essays [preview] Oedipus the King by Sophocles - Oedipus the King, was a play by Sophocles, it takes place in the city of Thebes. The city swept with a plague, it was just like the one in Athens (Kennedy 710). The plague encourages Oedipus to find and exile the man who murdered Laios, the former king. Throughout the play Oedipus portrays his ignorance and innocence, but then he begins to question his upbringings and realizes the truth about his life. ...Oedipus gets his name through a complex pun. Odia means to know (from the root vid-, see), pointing to the tales contrasting themes of sight and blindness, wisdom and ignorance (Kennedy 710).... [tags: thebes, plague, athens] :: 1 Works Cited 1053 words (3 pages) Strong Essays [preview] Oedipus the King: The Tragic Flaws Of Oedipus - The ancient Greeks were fond believers of Fate. Fate, defined according to Websters, is the principle or determining cause or will by which things in general are believed to come to be as they are or events to happen as the do. The Greeks take on Fate was slightly modified. They believed that the gods determined Fate: fate, to which in a mysterious way the gods themselves were subject, was an impersonal force decreeing ultimate things only, and unconcerned with day by day affairs. It was thought that these gods worked in subtle ways; this accounts for character flaws (called harmatia in Greek).... [tags: Oedipus Rex, Sophocles] 1052 words (3 pages) FREE Essays [view] Oedipus the King - Spanning a period of thirty years, Sophocles produced three plays all with similar thematic qualities. One such production features "a noble man who seeks knowledge that in the end destroys him" (70). Although, the Athenian audience was familiar with the original narrative of Oedipus Rex, spectators still found joy in watching the play unfold before them. In the play, Sophocles demonstrates to the audience through the main character that blindness is not necessarily limited to physical blindness, but can equally afflict intellectually capabilities.... [tags: Oedipus Rex Essays] 439 words (1.3 pages) FREE Essays [view] Oedipus the King - Sophocles' Oedipus Rex Sophocles Oedipus Rex has fascinated readers for over two millennia with its tale of a man who falls from greatness to shame. The enigmatic play leaves many questions for the reader to answer. Is this a cruel trick of the gods. Was Oedipus fated to kill his father and marry his mother. Did he act of his own free will. Like the Greeks of centuries past, we continue to ponder these perennial questions. Part of the genius of Sophocles is that he requires a great deal of mental and spiritual involvement from his audience.... [tags: Oedipus Rex, Sophocles] :: 6 Works Cited 2144 words (6.1 pages) Term Papers [preview] Oedipus the King - Oedipus seeks knowledge, but only up to a point Sophocles' classical Greek tragedy Oedipus the King is one of the centrepieces of Western literature. It also has a broader place in modern Western culture, courtesy of Dr Freud and his Oedipus complex, in which the process of growing up male is bound up with competition for the mother and the symbolic overthrow and supplanting, or ``killing', of the father. The play can be read as a traditional study of the "fatal flaw' theory of tragedy, in which Oedipus is brought down by hubris.... [tags: Oedipus Rex, Sophocles] 814 words (2.3 pages) FREE Essays [view] Ensnared by the Gods in Oedipus Rex - Ensnared by the Gods in Oedipus Rex A citizen of Periclean Athens may not have been familiar with the term entrapment, but he or she would surely have recognized the case of Oedipus as such. The tragedy of Oedipus is that he was ensnared by the gods. As Teiresias points out, "I say that with those you love best you live in foulest shame unconsciously" (italics mine) God is continuously indicted for having caused Oedipus troubles. The chorus asks, "What evil spirit leaped upon your life to your ill-luck?" And Oedipus himself is well aware of the source of his troubles: "It was Apollo, friends, Apollo, that brought this bitter bitterness, my sorrows to completion." Blinded an... [tags: Oedipus the King Oedipus Rex] 1143 words (3.3 pages) Strong Essays [preview] Oedipus the King - Strength Equals Downfall Aristotle defined a tragic story as the adventure of a good man who reaches his ultimate downfall because he pushed his greatest quality too far. Sophocles advocates the definition in the tragic play Oedipus Rex. He develops the play with the great polarities of fame and shame, sight and blindness, and ignorance and insight to show Oedipus’ experiences in search for knowledge about his identity. Through his search, Oedipus pushes his quest for truth too far and ultimately reaches his doom.... [tags: Oedipus Rex, Sophocles] 547 words (1.6 pages) FREE Essays [view] Oedipus the King: Fate, Destiny, and Symbolism - In the classic tale of Oedipus the King, the author uses Oedipus as a symbolic symbol of betrayal, nave, and despair. The tale in itself is a classic tragedy; it depicts characters in which is an act of betrayal, yet of the truth. Aristotle and Freud both have their own interpretation of the classic story of Oedipus. Aristotle idolizes tragedy in a significant manner as opposed to Freud emphasizing the true destiny and fate of Oedipus himself. Somehow, they are all juxtaposed into one complete symbolic meaning.... [tags: character analysis, thebes, sophocles] :: 2 Works Cited 960 words (2.7 pages) Better Essays [preview] Oedipus The King: Role Of Gods - Gods can be evil sometimes. In the play Oedipus the King, Sophocles defamed the gods reputation, and lowered their status by making them look harmful and evil. It is known that all gods should be perfect and infallible, and should represent justice and equity, but with Oedipus, the gods decided to destroy him and his family for no reason. It might be hard to believe that gods can have humanistic traits, but in fact they do. The gods, especially Apollo, are considered evil by the reader because they destroyed an innocent mans life and his family.... [tags: Oedipus Rex, Sophocles] 1054 words (3 pages) Strong Essays [preview] The Philosophy of Sophocles in Oedipus the King - o Structure: The play is divided into three parts. This is very logical. In The first part we have the problem and the accusation of Creon. In part two we have the discovery of the truth. At the end of the play we find the truth and the consequences of it. Oedipus admits his blindness, feels ashamed and is pious. The strengh of the dialogue is not felt as it is translated from Latin into English. o In what way classical and Greek drama are different from modern drama.

1. - greek drama is not concerned with the description of life.... [tags: Oedipus Rex Essays] 1019 words (2.9 pages) FREE Essays [view] Oedipus the King as a Tragic Hero - Oedipus as a Tragic Hero According to Aristotle's theory of tragedy and his definition of the central character, Oedipus the hero of Sophocles is considered a classical model of the tragic hero. The tragic hero of a tragedy is essential element to arouse pity and fear of the audience to achieve the emotional purgation or catharathis. Therefore, this character must have some features or characteristics this state of purgation. In fact, Oedipus as a character has all the features of the tragic hero as demanded by Aristotle.... [tags: Oedipus Rex Essays] 954 words (2.7 pages) Unrated Essays [preview] Oedipus the King: Reason and Passion - Oedipus the King: Reason and Passion In the play, Oedipus the King, there are dual parts of reason and passion. Oedipus primarily acts with both reason and passion at different stages in the play. There are several points in the play where Oedipus acts with reason. The first such point occurs when he is asked by his followers to help save Thebes. He acts with reason when he immediately decides to heed to their demands and find help for them. However, he may also have been deciding to do this through passion.... [tags: Oedipus Rex Essays] 1020 words (2.9 pages) FREE Essays [view] The Role of Teiresias in Sophocles' Oedipus Rex - The Role of Teiresias in Sophocles'Oedipus Rex (the King) Teiresias uses his psychic abilities to foreshadow the anguish and destruction that Oedipus will encounter after he learns the truths of his life. Teiresias is also responsible for further developing the theme of blindness by using his own physical blindness to reveal to Oedipus his mental blindness. Lastly, Teiresias is ultimately responsible for imposing dramatic irony because of his great knowledge of the truth of Oedipus. In the play, Oedipus Rex, by Sophocles, the minor character of Teiresias is responsible for foreshadowing Oedipus fate, developing the theme of blindness, and also illustrating dramatic irony.... [tags: Oedipus the King Oedipus Rex] :: 1 Works Cited 1417 words (4 pages) Powerful Essays [preview] Irony in Oedipus the King - Irony in Oedipus Rex Oedipus Rex, by the Greek playwright Sophocles, is, without a doubt, one of the greatest examples of dramatic irony. There are many instances where the audience knows so much more than the main characters, and Sophocles uses irony to point to Oedipus as Laius' murderer as well. Additionally, Oedipus is most definitely a tragic hero-he had a tragic flaw, namely that he was relentless and often rash in his search for the truth about Laius' death and his killer; this ultimately lead to Oedipus' own destruction.... [tags: Oedipus Rex, Sophocles] 545 words (1.6 pages) Unrated Essays [preview] Mythology in Oedipus Rex - Mythology in Oedipus Rex E. T. Owen in Drama in Sophocles Oedipus Tyrannus comments on the mythological beginnings of Oedipus Rex: Professor Goodell says: Given an old myth to be dramatized, Sophocles primary question was, Just what sort of people were they, must they have been, who naturally did and suffered what the tales say they did and suffered? That was his method of analysis (38). The Greek Sophoclean tragedy Oedipus Rex is based on a myth from the Homeric epic Odysseus.... [tags: Oedipus the King Oedipus Rex] :: 13 Works Cited 3973 words (11.4 pages) Powerful Essays [preview] Oedipus the King - Title In the play, Oedipus the King, blindness is used metaphorically and physically to characterize several personas , and the images of clarity and vision are used as symbols for knowledge and insight. Enlightenment and darkness are used in much the same manner, to demonstrate the darkness of ignorance, and the irony of vision without sight. they will never see the crime I have committed or had done upon me! These are the words Oedipus shouted as he blinds himself upon learning the truth of his past.... [tags: essays research papers] 461 words (1.3 pages) FREE Essays [view] Use of Dramatic Irony in Oedipus the King - In the play "Oedipus the King" by Sophocles, the author presents us with several instances of dramatic irony. Dramatic irony occurs when the meaning of the situation is understood by the audience but not by the characters in the play. Dramatic irony plays an important part in "Oedipus the King", because it is used to describe Oedipus' character as arrogant and blind toward the truth. The audience is expected to understand Oedipus' history well before he does. In the first three episodes, Oedipus uses a lot of dramatic irony in his speeches.... [tags: Oedipus Rex Essays] 406 words (1.2 pages) FREE Essays [view] Oedipus the King: A Painful Path to Truth - Truth in Oedipus Rex The play "Oedipus Rex" is a very full and lively one to say the least. Everything a reader could ask for is included in this play. There is excitement, suspense, happiness, sorrow, and much more. Truth is the main theme of the play. Oedipus cannot accept the truth as it comes to him or even where it comes from. He is blinded in his own life, trying to ignore the truth of his life. Oedipus will find out that truth is rock solid. The story is mainly about a young man named Oedipus who is trying to find out more knowledge than he can handle.... [tags: Oedipus Rex Essays] 742 words (2.1 pages) FREE Essays [view] Oedipus the King: Light vs. Dark - Light vs. Darkin Oedipus Throughout Oedipus the King, Sophocles employs one continuous metaphor: light vs. darkness, and sight vs. blindness. A reference to this metaphor occurs early in the play, when Oedipus falsely accuses Tiresias and Creon of conspiracy: Creon, the soul of trust, my loyal friend from the start steals against me... so hungry to overthrow me he sets this wizard on me, this scheming quack, this fortune-teller peddling lies, eyes peeled for his own profitseer blind in his craft.... [tags: Oedipus Rex Essays] 411 words (1.2 pages) FREE Essays [view] Self-Discovery and the Pursuit of Truth in Sophocles' Oedipus - Self-Discovery and the Pursuit of Truth in Sophocles' Oedipus It is said that the truth will set you free, but in the case of Sophocles Oedipus, the truth drives a man to imprison himself in a world of darkness by gouging out his eyes. As he scours the city for truth, Oedipus ruin is ironically mentioned and foreshadowed in the narrative. With these and other devices Sophocles illuminates the kings tragic realization and creates a firm emotional bond with the audience.... [tags: Oedipus Rex Essays] 1141 words (3.3 pages) Strong Essays [preview] Oedipus the King - Many times humans do things that contradict another thing they do. An example of this is one thing may be good but also bad at the same time. A person who has done this more then once is Oedipus in the writer Sophocles plays. Sophocles uses imagery like light verses darkness, knowledge verses ignorance and sight verses blindness. Oedipus is very knowledgeable during the play and at some times still extremely ignorant. He doesnt always put pieces together. When they are right in front of him. Many people in the play call him ignorant when he still believes that he is knowledgeable.... [tags: Oedipus Rex, Sophocles] 993 words (2.8 pages) FREE Essays [view] Sight and Blindness in Oedipus Rex - Sight and Blindness in Oedipus Rex Oedipus Rex is a play about the way we blind ourselves to painful truths that we cant bear to see. Physical sight and blindness are used throughout the play, often ironically, as a metaphor for mental sight and blindness. The play ends with the hero Oedipus literally blinding himself to avoid seeing the result of his terrible fate. But as the play demonstrates, Oedipus, the man who killed his father and impregnated his mother, has been blind all along, and is partly responsible for his own blindness.... [tags: Papers] 733 words (2.1 pages) Unrated Essays [preview] Antigone and Oedipus by Sophocles - Antigone & Oedipus By Sophocles are great stories of Tragedy and adversity. Creon, Oedipus and Antigone are truly engaged in struggle with reality, destiny and self-pity, for life. Oedipus The King is the tragic story of a man of a noble structure but is triggered by great tragedies and realities of him-self that shatter his existence. From the beginning of the story Oedipus is shown as a noble caring man. He is greatly worried about the plague in Thebes but my spirit grieves for the city, for myself and all of you he tells the priest and his people of Thebes, however He is also impetuous and suspicious of the motive of His friends; But these flaws may not be considered as a reason to... [tags: Tragedy, Creon, Oedipus] 794 words (2.3 pages) Better Essays [preview] Oedipus Rex: Imagery of Blindness and Sight as a Medium to the Themes - In the play, Oedipus Rex, written by Sophocles, an honourable and admirable Greek king named Oedipus rules the town of Thebes. He is left in mental turmoil and decay as his unknown, corrupt and immoral past is slowly revealed during his quest to find the culprit who murdered King Laius. The newly exposed past suddenly transforms his glory and respect into shame and humiliation. After he learns about his wicked past he stabs his eyes, which lead to his blindness. During the course of the play, references to blindness and vision constantly recur, giving the reader an enhanced and more insightful look into the themes of the play.... [tags: Theatre] 1225 words (3.5 pages) Strong Essays [preview] Oedipus Rex and Gilgamesh - 'No two men are alike in the way they act, the way they think, or the way they look. However, every man has a little something from the other. Although Oedipus and Gilgamesh are entirely different people, they are still very similar. Each one, in their own way, is exceptionally brave, heroically tragic, and both encompass diverse strengths and weaknesses. One is strictly a victim of fate and the other is entirely responsible for his own plight. Out of the two men, Gilgamesh was far braver than Oedipus.... [tags: Compare Contrast Oedipus the King] :: 2 Works Cited 1027 words (2.9 pages) Strong Essays [preview] Cesure and Sympathy in Oedipus the King - Sophocles translates his philosophy of life, of there being a harmony in the workings out of the universal order of things, into a harmony in Oedipus Rex. In the play, Oedipus, for instance, is a free agent with, however, certain limits upon his freedom of action as determined by the will of the gods; a transgression by Oedipus would lead to intervention by the gods since justice must prevail as is evident by the admission of chorus in the play ("But all eyes fail before time's eye, / All actions come to justice there.").... [tags: Oedipus Rex Essays] 637 words (1.8 pages) Unrated Essays [preview] Analysis of Oedipus the King - In Sophocles' Oedipus Rex, the theme of irony plays an important part throughout the play. In the play, Oedipus Rex believes that if he leaves Corinth he will be able to avoid his fate. The oracle says the Oedipus will kill his father and bear children with his mother. Eventually, he unknowingly kills his father in a chance meeting and married his mother. Oedipus remains clueless that the oracles prediction has come to pass. The play is a tragedy, and Oedipus is a tragic hero because he has an act of injustice, because his downfall is the result of his own fault, because he gains and as well as loses.... [tags: Oedipus Rex, Sophocles] 559 words (1.6 pages) FREE Essays [view] Oedipus the King - Irony is incongruity between the actual results of a sequence of events and the normal or expected results (Merriam Webster). This means that a person may think that something is going to happen based on what they see or what they believe, when in reality the exact opposite happens. Irony can be further specified as dramatic or tragic irony. These types of irony often occur in plays, stories, and movies; where viewers or readers are led in one direction and director or author reveals different results than what is expected.... [tags: Shakespearean Literature ] :: 9 Works Cited 2010 words (5.7 pages) Term Papers [preview] Oedipus the King and Antigone: Rationality Versus Emotionalism - Rationality is the quality or state of being agreeable to reason; it is this item that separates man from animal. Man and beast, however, still have something in common: in an emotional state, both are subject to acting irrationally. For instance, a normally very loving pet can become violent simply because one of his toys was taken away - not to say that he is no longer loving, he is just overwhelmed by anger. Likewise, in Sophocles's Oedipus Rex and Antigone, the protagonists Oedipus and Creon (who appears in both stories) exhibit a similar disposition as the "loving pet:" while they are usually reasonable, having their fates verbally revealed to them triggers an emotion that results in th... [tags: Oedipus Rex, Sophocles] 779 words (2.2 pages) Unrated Essays [preview] King Oedipus - King Oedipus by Sophocles Blindness is the downfall of the hero Oedipus in the play King Oedipus by Sophocles. Not only does the blindness appear physically, but also egotistically as he refuses to acknowledge the possibility of him actually being the murderer of Laius, the former King of Thebes. Coincidentally, he is also Oedipuss biological father. The use of light and dark in the play is strategically applied in order to better understand the emotion that lies within the characters. As blame is placed upon Oedipus for the murder of Laius, he blinds himself from the possible reality that he may be the killer.... [tags: essays research papers] 850 words (2.4 pages) Unrated Essays [preview] The Use of Religion as a Literary Element in Oedipus Rex - The Use of Religion as a Literary Element in Oedipus Rex and how it Influences the Use of Religion in Modern Western Literature Famous novelist, C.S. Lewis, stated, Literature adds to reality, it does not simply describe it. It enriches the necessary competencies that daily life requires and provides; and in this respect, it irrigates the deserts that our lives have already become (Literature Quotes).... 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Cataract. Photo courtesy of National Eye Institute, NIH

Cataracts are a clouding of the lenses in your eyes. They affect vision and are very common in older people. More than 22 million Americans have cataracts. They are the leading cause of blindness in the world. By age 80, more than half of all people in the United States either will have a cataract or have had cataract surgery.

Common symptoms are:

Treatment with new glasses, brighter lighting, anti-glare sunglasses, or magnifying lenses can help at first. Surgery is also an option. It involves removing the cloudy lens and replacing it with an artificial lens. Wearing sunglasses and a hat with a brim to block ultraviolet sunlight may help to delay cataracts.

Glaucoma. Photo courtesy of National Eye Institute, NIH

Glaucoma damages the eye's optic nerve and is a leading cause of blindness. It usually happens when the fluid pressure inside the eyes slowly rises, damaging the optic nerve. Often there are no symptoms at first, but a comprehensive eye exam can detect it. About 2.3 million Americans suffer from glaucoma. It is estimated that an additional 2 million have the disease but don't know it.

Glaucoma is a leading cause of blindness among African Americans and Hispanics. African Americans experience glaucoma at a rate three times that of whites. They suffer blindness four times more frequently. Between the ages of 45 and 64, glaucoma is 15 times more likely to cause blindness in African Americans than in whites.

People at risk should get eye exams at least every two years, especially:

Treatment usually includes prescription eye drops and/or surgery. There is no "cure" for glaucoma. Early diagnosis and treatment can control glaucoma before vision loss or blindness occurs. New research is focusing not only on lowering pressure inside the eye, but also exploring medications to protect and preserve the optic nerve from the damage that causes vision loss. There has been progress in understanding the genetics of glaucoma in the last few years, including the discovery of genes found to be associated with many forms of glaucoma.

Age-Related Macular Degeneration. Photo courtesy of National Eye Institute, NIH

Macular degeneration, often called age-related macular degeneration (AMD), is a leading cause of vision loss in Americans 60 and older. It is a disease that destroys the sharp, central vision needed to see objects clearly. This affects the ability to read, drive, watch television, and do routine daily tasks.

AMD affects the macula, the part of the eye that allows you to see fine detail. It does not hurt, but causes cells in the macula to die. In some cases, AMD advances so slowly that people notice little change in vision. In others, the disease progresses faster and may lead to vision loss in both eyes. There are two kinds of AMDwet and dry. Wet AMD occurs when abnormal blood vessels behind the retina start to grow under the macula. Dry AMD occurs when the light-sensitive cells in the macula slowly break down, gradually blurring central vision in the affected eye.

Treatment: Although there is no cure for AMD at this time, regular eye exams can detect the disease so treatment can be most effective. Findings from the NEI-supported Age-Related Eye Disease Study (AREDS) show that a specific combination of vitamins and minerals can help slow the progression of advanced AMD. Treatments for wet AMD include laser surgery, photodynamic therapy, and drugs injected into the eye. The NEI recently started a clinical trial to compare the relative safety and effectiveness of two drugs currently used to treat wet AMD. The two drugs, which are injected into the eye, are Lucentis (ranibizumab) and Avastin (bevacizumab). NEI is also supporting AREDS2 to learn whether a modified combination of vitamins and minerals can further help people with AMD.

Diabetic retinopathy is caused by diabetes. It affects the retina, the light-sensitive tissue at the back of the eye, and causes the most blindness in U.S. adults. It affects the vision of more than half of the 18 million people diagnosed with diabetes age 18 or older.

People with diabetes should have a complete eye exam through dilated pupils at least once a year.

Treatment: Diabetic retinopathy is treated with surgery or laser surgery. With timely treatment; adequate control of blood sugar, blood pressure, and cholesterol levels; and regular follow up, 90 percent of all cases of blindness from diabetes can be prevented.

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Leading Causes of Blindness

Select Search World Factbook Roget's Int'l Thesaurus Bartlett's Quotations Respectfully Quoted Fowler's King's English Strunk's Style Mencken's Language Cambridge History The King James Bible Oxford Shakespeare Gray's Anatomy Farmer's Cookbook Post's Etiquette Brewer's Phrase & Fable Bulfinch's Mythology Frazer's Golden Bough All Verse Anthologies Dickinson, E. Eliot, T.S. Frost, R. Hopkins, G.M. Keats, J. Lawrence, D.H. Masters, E.L. Sandburg, C. Sassoon, S. Whitman, W. Wordsworth, W. Yeats, W.B. All Nonfiction Harvard Classics American Essays Einstein's Relativity Grant, U.S. Roosevelt, T. Wells's History Presidential Inaugurals All Fiction Shelf of Fiction Ghost Stories Short Stories Shaw, G.B. Stein, G. Stevenson, R.L. Wells, H.G. Verse > Anthologies > Arthur Quiller-Couch, ed. > The Oxford Book of English Verse CONTENTSBIBLIOGRAPHIC RECORD Arthur Quiller-Couch, ed. 1919. The Oxford Book of English Verse: 12501900. John Milton.16081674 318.On His Blindness WHEN I consider how my light is spent E're half my days, in this dark world and wide, And that one Talent which is death to hide, Lodg'd with me useless, though my Soul more bent To serve therewith my Maker, and present 5 My true account, least he returning chide, Doth God exact day-labour, light deny'd, I fondly ask; But patience to prevent That murmur, soon replies, God doth not need Either man's work or his own gifts, who best 10 Bear his milde yoak, they serve him best, his State Is Kingly. Thousands at his bidding speed And post o're Land and Ocean without rest: They also serve who only stand and waite.

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318. On His Blindness. John Milton. The Oxford Book of ...

Red Green Color Blindness

Red Green Color blindness is predominantly found only in men. The gene that leads to red green color blindness is found in the X Chromosome. Males only have one X chromosome whereas females have 2; typically in females the stronger chromosome takes precedence so theyretain correctvision.The son of a woman carrying a faulty gene has a 50% chance of inheriting the faulty X chromosome and as a result suffering from color blindness. The daughter of the same woman is unlikely to be color blind unless her father is color blind; however she retains a 50% chance of being a carrier for the defective gene.

Blue color blindness (often referredto as blue yellow color blindness) is extremely rare, so rare that only 5% of color blind people suffer from it.Unlike red green color blindness, the chance of having blue color blindness is equal in both men and women as the gene is found on a different chromosome ( chromosome 7). This gene is shared equally by men and women and blue color blindness comes from a mutation of this gene.

One might expect the percentage of affected people to be relatively constant in all countries however this is far from the truth. In most Caucasian societies up to 1 in 10 men suffer, however only 1 in 100 Eskimos are color blind. There is no solid proof as to the cause of this however it is logical to assume that less of the original Eskimos carried the defective gene, so the likelihood of it infecting the gene pool was quite a lot lower.

Whilst almost all color blindness is inherited, infrequently a change in the chromosome during early development can cause color blindness. Various injuries involving trauma to the eye, and even some diseases can also cause color blindness to develop in a person of any age.

As mentioned elsewhere on this website, cataracts are not a form of color blindness, so you wont see them in the table below. Cataracts are a clouding that develops in the crystalline lens of the eye, and have the effect to dull colors, and blur vision. It is not common to mistake someone with cataracts as someone who is color blind, as color blindness normally becomes apparent early in life, whereas cataracts dont usually form until ones senior years. However if you are unsure, you can take the freeonlinetests available on this website in the menu on the left to find out now.

The Below table displays the percentage of men and women suffering the different forms of color blindness, you can click on each defectto learn more about it.

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Prevalence Color Blindness