Amblyopia Essay examples

Visual agnosia refers to the “…inability to recognize objects that results neither from general intellectual loss nor from a loss of basic sensory abilities,” (Anderson, 2009, p. 32). There are generally two types of visual agnosia: apperceptive agnosia and associative agnosia. Apperceptive agnosia is the inability to recognize or draw simple shapes as they are shown or represented. Associative agnosia is the ability to recognize and copy drawings of simple and complex shapes. However, person with associative agnosia are unable to recognize the complex objects (Anderson, 2009).

Gibson’s and Gregory’s theories of perception both suggest that eye-retina is important for perception. The both believe that without eye-retina, a person will not be able to see. This is a common view of both of the theories of perception. The idea is supported by the case of SB. SB was a man who had been blind from birth due to cataracts. When he was 52, he had an operation which restored his sight and hence he could see. Thus, this case has shown the importance of eye-retina for things to be perceived. And therefore, supports both of theories of perception which eye-retina is essential for perception.

A medical definition of vision impairment is a sine qua non that prohibits 20/20 vision in one or both eyes (Bowman, Bowman, Dutton & Royal National Institute for the Blind, 2001; Vision Australia, 2015; Webster & Roe, 1998). Examples of vision impairment include, cataracts, which has the lens inside the eye increasingly cloudy; albinism, which is passed down genetically affecting clear vision and causes sensitivity to bright light; optic nerve damage, which affects field of vision as those nerves controlling vision are disrupted; macular degeneration, where parts of the retina that control colour and fine details are affected; retinitis pigmentosa, which is an ongoing reduction of the field of vision available and nystagmus, where the eye flickers involuntary (Bowman, Bowman, Dutton & Royal National Institute for the Blind, 2001; American Foundation for the Blind, 2015; Vision Australia, 2015 ; Baton Rouge Regional Eye Bank, 2015). John suffers from retinitis

     Cau yon reab mwat I aw mriting? If yon caunot reab it waybe is is decanse this is hom a persou with byslexia wight reab somethiug. A person with dyslexia has a very difficult lifestyle to live. To understand dyslexia you must be aware of the causes, effects strategies, and teaching methods for coping with the disease. “Dyslexia means having difficulty with words in reading, spelling and writing – in spite of having normal intelligence and ability” (Make the Connection).

After investigating spatial cognition and the construction of cognitive maps in my previous paper, "Where Am I Going? Where Have I Been: Spatial Cognition and Navigation", and growing in my comprehension of the more complex elements of the nervous system, the development of an informed discussion of human perception has become possible. The formation of cognitive maps, which serve as internal representations of the world, are dependent upon the human capacities for vision and visual perception (1). The objects introduced into the field of vision are translated into electrical messages, which activate the neurons of the retina. The resultant retinal message is organized into several forms of sensation and is

Ramachandran is helping to understand is the blindsight syndrome. Blindsight syndrome is when the person is completely blind, but can see. This is a rare syndrome seen in brain trauma patients. Graham Young has had this condition since he was eight years old, due to a horrific traffic accident. Graham can see to the left, but is unable to visualize anything on the right side. He is able to see an object move or the orientation of it, but cannot comprehend the object. Graham lacks the ability to be consciously aware of wait is being seen. People do not only just see objects, but they also interpret the information. According to Dr. Ramachandran, there are two ways the brain visualizes objects (Rawlene, 2014). The cerebral cortex pathway is from the eyeball through the thalamus to the visual cortex of the brain, which allows you to be visually conscious of what you are seeing (Rawlene, 2014). The other pathway to see is through the central core (Rawlene, 2014). The central core is located near the base of the stem of the brain, which is then transmitted to the visual cortex (Rawlene, 2014). The central core is closely related to lower life forms, such as a cat (Rawlene, 2014). This connection is more concern with the survival of the species and necessary reflexes (Rawlene, 2014). Blindsight syndrome happens when there is damage to just the cerebral cortex pathway. Graham Young‘s condition is a prime example of how the brain needs to

Another visual condition that has intrigued the neurologist for over a century is a condition called visual neglect. After having a stroke in her parietal lobes in her brain, Peggy Palmer had normal vision, which should allow her to draw a copy an image without difficulty. When Peggy was asked to draw a copy of a daisy, they found that she only would draw the right half of the daisies image. She didn’t realize this until the it was told to her, then she could see that she in fact was missing the entire left half of the daisy. Dr. Ramachandran explains that as we see an object, the visual input will split into two different pathways. One is the “how?” and the other is the “what?”. The “how” deals with the area of the brain that mainly controls

We hypothesized that the resulting effects that participants would experience in the contrived situation would be limited to stereopsis, reduced field of vision, and impaired hand-eye coordination in the performance of activities of daily living. These impairments would make activities of daily living significantly more difficult for someone who has acutely lost vision in one of their eyes.

The development of the human body is an exquisite process that involves numerous complicated processes for even the smallest of body parts, including the eyes. The eyes are an extraordinarily complex organ capable of gathering information through refracted light and sending it the brain to assemble a picture. They provide the ability to see and follow a moving object and the capability to tell an approximate distance of an object. When light passes through the cornea and iris pupil, at the anterior portion of the eye, it is focused by the lens onto the retina at the back of the eye. Photoreceptor cells, which are present in the retina, detect the light and send information to interneurons which begin to sort out the information. This information is then sent to ganglion cells which transmits the final information to the brain (Sowden 199). Because the eyes have such complicated and exquisite processes, the likelihood of developmental errors occurring are possible. A large number of these developmental errors lead to congenital defects and abnormalities that effect the individual’s eye sight. Some of these defects and abnormalities can cause serious diseases and syndromes that effect more than just the eyes, but also neurological processes, facial dimorphisms, growth failure, tracheal development, and genitalia anomalies.

Phase 2: Retina is placed in the back side of the eye and it has to „collaborate“ with cornea and lens in order to provide an image for

However, at its head, there is a blind spot because there are no photoreceptors in this part of

Another patient of Dr. Ramachandran is Gram Young, who at the age of 8 lost his sight in a road accident that caused brain damage to main visual center which takes up half of the large region in the back of the brain. Gram explained that he would walk into things as big as pillars much like those at a train station because he couldn’t see them, but he can still see. It’s a very rare paradoxical condition referred to as blind sight. This condition allows the patient to detect a thing, but isn’t aware of what it is. Gram can see to the left, but is blind to everything on the right in both eyes. To test this Collin Blakemore an Oxford scientist, used a panel divided by line down the middle, the left side white, while the right side a light blue, of which Gram couldn’t see. When placing something in Gram’s field of vision on the left he can see it if

The book “Melal “by Robert Barclay takes place in 1981 in The Marshall Islands of the South Pacific. The people known as the Marshallese are the natives to these islands. Overtime other cultures began to settle on these islands also, such as the Spanish, Japanese, and Americans. Out of these three cultures the Americans were the most domineering and devastating to the Marshallese people. The Americans took over the Marshallese native land and forced all of them to live on one island in deplorable conditions. The Marshallese had their freedom revoked from them; they then had to live under the Americans rules. Two of the Marshallese characters in this story who believes strongly in withholding many of the native

Visual acuity is a measure of an observer’s ability to see fine spatial detail (Cavonius & Schumacher, 1966). There are a number of factors that affect visual acuity, such as illumination and contrast, and various ways to measure it (Kalloniatis & Luu, 2005). One way to measure visual acuity is through target detection which requires the perception of the orientation of a stimulus such as a Landolt C or a Snellen E (Kalloniatis & Luu, 2005). The participant in the current experiment was referred to have their acuity tested. Target detection of a stimulus was used to measure the participant’s visual acuity as a function of retinal eccentricity of the target.

Normal vision occurs by a coordinated synthesis of the retinal images into a single brain image. If, however, one of the eyes does not transmit a coordinated or useful image the brain may choose to ignore this image when conducting its synthesis. The region of the