what is a chiasm in vision
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Optic chiasma The optic chiasm or optic chiasma is an X-shaped space, located in the forebrain, directly in front of the hypothalamus.Crucial to vision, the left and right optic nerves intersect at the chiasm, thus creating the hallmark X-shape.One-half of each nerve's axons (their long, threadlike portions) enters the opposite tract at this location, making it a partial decussation (crossing).hile rare, optic gliomas — tumors — can grow within the chiasm or in conjunction with hypothalamic tumors. Gliomas can directly affect the optic nerves. Benign (noncancerous) and typically occurring before age 20, symptoms of optic glioma can include: 1  Bulging eyes or vision loss.
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optic chiasm optic chiasm a structure in the forebrain formed by the decussation of fibers of the optic nerve from each half of each retina.
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Optic nerve 1 Damage to the optic nerve anterior to the optic chiasm causes loss of vision in the eye on the same side as the damage.  Damage at the optic chiasm typically causes loss of vision laterally in both visual fields (bitemporal hemianopsia). It may occur with large pituitary tumors pituitary adenoma.
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What Is a Chiastic Structure? A chiastic structure, also known as a ring structure or chiastic pattern, is a literary device used to emphasize parallel ideas. Chiasms are considered a branch of form criticism. Examples of chiastic patterns can be seen in many books, including classics such as the Bible and Paradise Lost..
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- Astigmatism is a common vision condition that happens when a person's cornea is not symmetrical. A normal cornea is round like a baseball. With astigmatism, the cornea curves more severely, like a football. View an Astigmatism demo.
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Common Vision Problems Astigmatism is a vision condition that causes blurred vision due either to the irregular shape of the cornea, the clear front cover of the eye, or sometimes the curvature of the lens inside the eye.stigmatism occurs due to the irregular shape of the cornea or the lens inside the eye. The cornea and lens are primarily responsible for properly focusing light entering your eyes allowing you to see things clearly.
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Chiasmal syndrome Middle chiasmal syndrome relates to the decussating fibers in the body of the optic chiasm while posterior chiasmal syndrome involves the caudal fibers. The classic anterior chiasmal lesion affects the optic nerve fibers and the contralateral inferonasal fibers located in Wilbrand’s knee.
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Optic glioma 1 One or both of the optic nerves that carry visual information to the brain from each eye.  The optic chiasm, the area where the optic nerves cross each other in front of the hypothalamus of the brain.
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Not All LinkedIn Skills Are Created Equal: How to Pick the Right Ones First, you want to start high level. Pick a Skill that is all encompassing for what you do. Using the skills’ pages’ auto-suggest, begin typing the name of your Skill. LinkedIn will suggest the most commonly used version of that name. Open up that skills page and add it to your profile if its not already there. Step 2: Filter Down to More Targeted Skills. Once you’re on the high-level skills page, there are a number of important research tools available to you. Next, look for the graph called Relative Growth on the top right of the page:
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Toric Lens Implants Astigmatism is a refractive error where people are unable to see objects clearly from a distance or up close. Astigmatism is asymmetric steepening of the cornea or natural lens causes light to be focused unevenly. Astigmatism may occur in varying degrees in each eye and can accompany myopia or hyperopia.
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Central Scotoma Central Scotoma A central scotoma is a grey, black or blind spot in the middle of one's vision. This central blind spot can be due to geographic atrophy (advanced dry macular degeneration) or to the damage of photoreceptor cells from choroidal neovascularization (leaking blood vessels). Scotoma Causes.
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- The optic chiasm or optic chiasma is an X-shaped space just in front of the pituitary gland where optic nerve fibers pass through to the brain.
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Chiasmus Figure of Speech In rhetoric, chiasmus is a verbal pattern (a type of antithesis) in which the second half of an expression is balanced against the first with the parts reversed. Essentially the same as antimetabole.
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Scotoma A scotoma (Greek σκότος/ skotos, skótos; darkness: plural scotomas or) scotomata is an area of partial alteration in the field of vision consisting of a partially diminished or entirely degenerated visual acuity that is surrounded by a field of – normal or relatively-well – preserved. vision scotoma can be a symptom of damage to any part of the visual system, such as retinal damage from exposure to high-powered lasers, macular degeneration and brain damage. The term scotoma is also used metaphorically in several fields.
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The Optic Nerve visual pathway. As the optic nerve leaves the back of the eye, it travels to the optic chiasm, located just below and in front of the pituitary gland (which is why a tumor on the pituitary gland, pressing on the optic chiasm, can cause vision problems).isual pathway. As the optic nerve leaves the back of the eye, it travels to the optic chiasm, located just below and in front of the pituitary gland (which is why a tumor on the pituitary gland, pressing on the optic chiasm, can cause vision problems).
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- Chiasmal syndrome. Chiasmal syndrome is the set of signs and symptoms that are associated with lesions of the optic chiasm, manifesting as various impairments of the sufferer's visual field according to the location of the lesion along the optic nerve.
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What Is the Optic Chiasm and How Does it Affect Vision? The optic chiasm is an X-shaped structure formed by the crossing of the optic nerves in the brain. The optic nerve connects the brain to the eye. At the optic chiasm, nerve fibers from half of each retina cross over to the opposite side of the brain. The fibers from the other half of the retina travel to the same side of the brain. Because of this junction, each half of the brain receives visual signals from the visual fields of both eyes.
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- Medical Definition of chiasma. plural. chiasmata. \-mət-ə\play. 1: an anatomical intersection or decussation—see optic chiasma. 2: a cross-shaped configuration of paired chromatids visible in the diplotene of meiotic prophase and considered the cytological equivalent of genetic crossing-over.
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The Optic Nerve In the optic chiasm, the optic nerve fibers emanating from the nasal half of each retina cross over to the other side; but the nerve fibers originating in the temporal retina do not cross over.
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What Is the Optic Chiasm and How Does it Affect Vision? The optic chiasm is an X-shaped structure formed by the crossing of the optic nerves in the brain. The optic nerve connects the brain to the eye. At the optic chiasm, nerve fibers from half of each retina cross over to the opposite side of the brain. The fibers from the other half of the retina travel to the same side of the brain.
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- Information from the. retina leaves the eye through the optic nerve, which. leads to the optical chiasm. Here, the ﬁbers from the. nasal side of the fovea in each eye cross over to the. opposite side of the brain while the others remain on. the same side.
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- The optic nerve is a motor nerve that connects the retina of the eye with the brain. This nerve penetrates the choroid and the sclera from the rear of the eye at the optic disc where it is met with the other optic nerve to form the optic chiasma.
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chiasma Medical Definition of CHIASMA. 1. : an anatomical intersection or decussation—see optic chiasma. 2. : a cross-shaped configuration of paired chromatids visible in the diplotene of meiotic prophase and considered the cytological equivalent of genetic crossing-over.
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What is the Optic Chiasma? In this way, the brain merges all of the data concerning the same side of the body together in the optic chiasma to form an optic tract, which travels from the chiasm to the visual centers of the brain. Compression by a tumor or disruption of blood flow to the area may damage the optic chiasma.
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- Chiasma. The cross-shaped exchange configuration between non sister chromatids of homologous chromosomes that is visible during prophase I of meiosis. chiasma The site where the exchange of chromosome segments between homologous chromosomes takes place (crossing-over) (pl.: chiasmata). PICTURE
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- BASIC VISUAL PATHWAYS. A. The pathway: Vision is generated by photoreceptors in the retina, a layer of cells at the back of the eye. The information leaves the eye by way of the optic nerve, and there is a partial crossing of axons at the optic chiasm.After the chiasm, the axons are called the optic tract.ASIC VISUAL PATHWAYS. A. The pathway: Vision is generated by photoreceptors in the retina, a layer of cells at the back of the eye. The information leaves the eye by way of the optic nerve, and there is a partial crossing of axons at the optic chiasm.