Human visual hardware is a result of a billion years of evolution within the earths atmosphere where light is scattered by molecules of air, moisture, particular matter etc. However as we ascend into our atmosphere with decrease density, light distribution is changed resulting in our visual hardware receiving visual data in different format.
Some Aspects to Consider: 1. Visual acuity is the degree to which the details and contours of objects are perceived. Visual acuity is usually defined in terms of minimum separable.Large variety of factors influence this complex phenomenon which includes : # Optical factors- state of the image forming mechanisms of the eye.
# Retinal factors such as the state of the cones. #
Stimulus factors such as illumination, brightness of the stimulus, contrast between the stimulus and background, length of time exposed to the stimulus. * Minimum separable: shortest distance by which two lines can be separated and still be perceived as two lines. "During the day, the earth has a predominantly bluish cast..... I could detect individual houses and streets in the low humidity and cloudless areas such as the Himalaya mountain area.... I saw a steam locomotive by seeing the smoke first..... I also saw the wake of a boat on a large river in the Burma-India area... and a bright orange light from the British oil refinery to the south of the city (Perth,Australia.)"
The above observation was made by Gordon
Cooper in Faith 7 [1963] and which generated much skepticism in the light of the thesis by
Muckler and Narvan "Visual Surveillance and
Reconnaissance from space vehicles" in which they determined that a visual angle of ten minutes was the operational minimum, and that the minimum resolvable object length [M.R.O.L] at an altitude of 113 miles would be 1730 ft. This limitation of acuity was revised the next year to 0.5 seconds of arc for an extended contrasting line and 15 seconds of arc for minimum separation of two points sharply contrasting with the background. Orbiting at 237 miles in the skylab it was possible to see the entire east coast [Canada to Florida Keys] and resolve details of a 500 feet long bridge based on inference. Of Interest is the fact that even though the mechanical eye [camera systems] can resolve objects greater than fifty times better than the human eye, without the human ability to infer, interpretation of the data is meaningless. Conclusion: Visual acuity in space exceeds that of earth norm when objects with linear extension such as roads, airfields, wake of ships etc. 2. Stereoscopic vision: the perception of two images as one by means of fusing the impressions on both retinas. In space one has to deal with a poverty of reference points.
One wonders what takes place in the brain to cause such phenomenal differences in perception. The cause is unknown for certain, like many things in the realm of science it has not been researched nearly enough, but there are some indications.
Helplessness is a category of psychological sickness that makes people feel lugubrious and desperate to despair imprisonment from freedom. The Third Eye, which can be also called metacognition, is an asset that people have the inner critique to think about the way they behave responsibly and maturely.
Peripheral vision is used amongst every species ranging from a deep-sea marine animal to a bird flying hundreds of feet above the ground. However, each species’ vision differs to some degree and also differentiates within the species itself. This can be due to various types of eye conditions.
In the movie, The Divine Secrets of the Ya-Ya Sisterhood, Callie Khouri directs something of a powerful story between a mother and her daughter. The movie Life as a House (Wrinkler, 2002) tells something of the same; of a father and the fight for the love of his son. The two movies both portray the fight between parents and their children. The commonality between father and son and mother and daughter is portrayed through the troublesome children and the problems that they face together. The “abuse “ that these children have received has formed them into the people they are today. What these characters had become is something that they do not want to be. As we age, we begin to discover the importance of family as depicted through Life as a House and The Divine Secrets of the Ya-Ya Sisterhood.
Myopia is defined as nearsightedness, which exists when the refractive elements of the eye (cornea and lens) place the image in front of the retina. The myopic condition is common in infants but generally levels off to normal vision as the infant ages (Vander & Gault, 1998). Myopia occurs in about 25% of the adult U.S. population. Many adults use corrective lenses or contacts to correct their myopic vision to 20/20 vision (Drexler et al., 1998). Many people find contacts or glasses hindering in their personal and/or professional lifestyle. For example, military pilots cannot wear glasses while flying and some firemen may find glasses too dangerous to wear during a rescue attempt. There is refractive surgery available to correct myopic eyes, like Photorefractive Keratectomy (PRK). Why do people have myopia, what can be done to correct myopia, and what are the results of corrective surgical procedures? These are a few questions that will be addressed and analyzed.
Based upon the accounts he introduced and explained, to see the environment is to willingly use all available senses and to interact with all spaces, consciously and physically. The validity of reality is then brought into question, which Sack suggests that those with sight may be blind to reality. Those with sight are prone to rely heavily on specific connections and ignore other vital ones. Ignored connections may deny unimaginable sensory enrichment and enable narrowed perceptions, which is how sighted individuals remain blinded and unaware of the gravity of oneself and the physical space one inhabits.
"Perception - Definition of Perception by the Free Online Dictionary, Thesaurus and Encyclopedia." Dictionary, Encyclopedia and Thesaurus - The Free Dictionary. Web. 08 Feb. 2011. .
5) Pattern of neuronal activity associated with conscious and unconscious processing of visual signals, Sahraie, et al.
An optometrist's job is usually to perform different tests and exams on a patient. The exams can reveal what could be wrong with someone’s eyes and the tests can usually tell the doctor the patient’s prescription. From that point the doctor can decide what kind of glasses they would need, either single vision, which are only for people who have a difficult time seeing further away, reading glasses, or bifocals that can help someone see up close and further away (Dickerhoof). Aside from performing exams, Optometrists can diagnose diseases in the eye, such as a cataract, perform minor procedures, provide treatments for things such as vision therapy or low vision rehab, and provide preoperative and postoperative care. Many of them counsel patients
In the novel The Great Gatsby, by F. Scott Fitzgerald, there are many important themes in the eyes of Dr. T.J. Eckleburg. The billboard was constructed to advertise a business of an oculist, symbolizing the growth of commercialism in America. The eyes watch the main characters as they pass the billboard on their way towards New York City, almost like a godly figure. At the beginning of the novel we see the setting as being described as a very terrible, grey land. As the eyes of Dr. T.J. Eckleburg appear over the hills people notice the billboard featuring a colorful blue background and the large eyes that give a sense of a godly figure in the heavens. As the eyes look down below they also see all of the lost morals and disdainful actions people do, thus symbolizing the corruption of the people. At the beginning we only see a billboard, but towards the end, the eyes mean so much more than that.
The eye is an extremely diverse organ, ranging in complexity across and within animal phyla. Here, a comparative approach is taken to outlining the diversity of the eye forms within vertebrates and invertebrates. The eye morphology of a variety of organisms was examined. Eye function, and placement on the body was also considered. Here, variation in eye form is discussed in relation to the environment the organism is adapted to. It is shown that an organisms eye morphology functions optimally for the ecological niche it occupies. Evolutionary analysis is used to account for the emergence of the different eyes. Convergent evolution is used to justify the similarities in eye types seen in organisms of different species. This analysis begins with the simplest of eye forms composes of single cells, present in the zooplankton larvae. Such primitive forms are identified in mollucs, annelids, cnidarians, and are then compared to more advanced eye forms contain lenses. This comparative approach provides a breadth of examples of vertebrates and invertebrates, making visible, the diversity of eye morphology within the animal kingdom.
Color depends on how much of the pigment melanin you have in the color part of your eyes. The more pigment the darker the eye color. The lighter the color is because of the less amount of melanin there is in the iris. Cataracts are the clouding of the lens that prevents light from entering. Double vision, decrease in vision, fuzziness, and blurriness could all be problems when bright light occurs. Causes of cataracts could be from smoking, diabetes and also excessive exposure to light. The function or purpose of the retina is to receive the light that the lens captures, turn the color of the light seen into neuro signals and send those signals to the brain for recognition. This is knowing the difference between light and dark. Floaters are
Have you ever wondered how your eyes worked? How you see things? How colors appear to you? And what you actually aren’t seeing? There are many different ways our eyes work, and thankfully everyone’s eyes are different in their own way. Doctors today are still finding out new things about how our eyes work, and new ways to fix our eyes so we can see better, or even fix little in corrections our eyes make. Have you ever looked at an object in front of you and still were able to see more objects around it, but not clearly? Those inconveniences are called blind spots. Many people are unaware about blind spots in their eyes, or what colors their eyes are actually seeing. A blind spot is a gap in your vision that causes you to see things out of the corner of your eyes, or see everything at once that can sometimes occur blurry to some people. Most of everyone has a blind spot in their eyes, and don’t even notice it. This anatomy review considers whether you have blind spots in your eyes, and how well you notice things with your eyes. I will answer the following questions:
The human eye has a natural blind spot that is completely unavoidable. This spot is where the optic nerve, sending what is being seen, connects to the brain. This nerve passes through the retina causing what is called the “blind spot”. The “blind spot” is a hole being created in the light sensitive tissue. While the image being seen is being sent to the brain it will
The Eye is the organ of sight. Eyes enable people to perform daily tasks and to learn about the world that surrounds them. Sight, or vision, is a rapidly occurring process that involves continuous interaction between the eye, the nervous system, and the brain. When someone looks at an object, what he/she is really seeing is the light that the object reflects, or gives off.