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Anopsia
An anopsia () is a defect in the visual field. If the defect is only partial, then the portion of the field with the defect can be used to isolate the underlying cause. Types of partial anopsia: *Hemianopsia **Homonymous hemianopsia **Heteronymous hemianopsia ***Binasal hemianopsia ***Bitemporal hemianopsia **Superior hemianopia **Inferior hemianopia *Quadrantanopia Quadrantanopia, quadrantanopsia, refers to an anopia (loss of vision) affecting a quarter of the visual field. It can be associated with a lesion of an optic radiation. While quadrantanopia can be caused by lesions in the temporal and parieta ... References External links Visual disturbances and blindness {{eye-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemianopsia
Hemianopsia, or hemianopia, is a loss of vision or blindness (anopsia) in half the visual field, usually on one side of the vertical midline. The most common causes of this damage are stroke, brain tumor, and trauma. This article deals only with permanent hemianopsia, and not with transitory or temporary hemianopsia, as identified by William Wollaston PRS in 1824. Temporary hemianopsia can occur in the aura phase of migraine. Etymology The word ''hemianopsia'' is from Greek origins, where: * ''hemi'' means "half", * ''an'' means "without", and * ''opsia'' means "seeing". Types When the pathology involves both eyes, it is either homonymous or heteronymous. Homonymous hemianopsia Paris as seen with left homonymous hemianopsia. A homonymous hemianopsia is the loss of half of the visual field on the same side in both eyes. The visual images that we see to the right side travel from both eyes to the left side of the brain, while the visual images we see to the left sid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heteronymous Hemianopsia
Hemianopsia, or hemianopia, is a loss of vision or blindness (anopsia) in half the visual field, usually on one side of the vertical midline. The most common causes of this damage are stroke, brain tumor, and trauma. This article deals only with permanent hemianopsia, and not with transitory or temporary hemianopsia, as identified by William Wollaston PRS in 1824. Temporary hemianopsia can occur in the aura phase of migraine. Etymology The word ''hemianopsia'' is from Greek origins, where: * ''hemi'' means "half", * ''an'' means "without", and * ''opsia'' means "seeing". Types When the pathology involves both eyes, it is either homonymous or heteronymous. Homonymous hemianopsia Paris as seen with left homonymous hemianopsia. A homonymous hemianopsia is the loss of half of the visual field on the same side in both eyes. The visual images that we see to the right side travel from both eyes to the left side of the brain, while the visual images we see to the left side i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homonymous Hemianopsia
Hemianopsia, or hemianopia, is a visual field loss on the left or right side of the vertical midline. It can affect one eye but usually affects both eyes. Homonymous hemianopsia (or homonymous hemianopia) is hemianopic visual field loss on the same side of both eyes. Homonymous hemianopsia occurs because the right half of the brain has visual pathways for the left hemifield of both eyes, and the left half of the brain has visual pathways for the right hemifield of both eyes. When one of these pathways is damaged, the corresponding visual field is lost. Signs and symptoms Paris as seen with right homonymous hemianopsia Mobility can be difficult for people with homonymous hemianopsia. "Patients frequently complain of bumping into obstacles on the side of the field loss, thereby bruising their arms and legs." People with homonymous hemianopsia often experience discomfort in crowds. "A patient with this condition may be unaware of what he or she cannot see and frequently bumps ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bitemporal Hemianopsia
Bitemporal hemianopsia, is the medical description of a type of partial blindness where vision is missing in the outer half of both the right and left visual field. It is usually associated with lesions of the optic chiasm, the area where the optic nerves from the right and left eyes cross near the pituitary gland. Causes In bitemporal hemianopsia, vision is missing in the outer (temporal or lateral) half of both the right and left visual fields. Information from the temporal visual field falls on the nasal (medial) retina. The nasal retina is responsible for carrying the information along the optic nerve, and crosses to the other side at the optic chiasm. When there is compression at optic chiasm, the visual impulse from both nasal retina are affected, leading to inability to view the temporal, or peripheral, vision. This phenomenon is known as bitemporal hemianopsia. Knowing the neurocircuitry of visual signal flow through the optic tract is very important in understanding bitem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binasal Hemianopsia
Binasal hemianopsia is the medical description of a type of partial blindness where vision is missing in the inner half of both the right and left visual field. It is associated with certain lesions of the eye and of the central nervous system, such as congenital hydrocephalus. Causes In binasal hemianopsia, vision is missing in the inner (nasal or medial) half of both the right and left visual fields. Information from the nasal visual field falls on the temporal (lateral) retina. Those lateral retinal nerve fibers do not cross in the optic chiasm. Calcification of the internal carotid arteries can impinge the uncrossed, lateral retinal fibers, leading to loss of vision in the nasal field. Clinical testing of visual fields (by confrontation) can produce a false positive result, particularly in inferior nasal quadrants. Management Etymology The absence of vision in half of a visual field is described as ''hemianopsia''. The absence of visual perception in one quarter of a vis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Field
The visual field is the "spatial array of visual sensations available to observation in introspectionist psychological experiments". Or simply, visual field can be defined as the entire area that can be seen when an eye is fixed straight at a point. The equivalent concept for optical instruments and image sensors is the field of view (FOV). In optometry, ophthalmology, and neurology, a visual field test is used to determine whether the visual field is affected by diseases that cause local scotoma or a more extensive loss of vision or a reduction in sensitivity (increase in threshold). Normal limits The normal (monocular) human visual field extends to approximately 60 degrees nasally (toward the nose, or inward) from the vertical meridian in each eye, to 107 degrees temporally (away from the nose, or outwards) from the vertical meridian, and approximately 70 degrees above and 80 below the horizontal meridian. The binocular visual field is the superimposition of the two monocular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anopia
An anopsia () is a defect in the visual field. If the defect is only partial, then the portion of the field with the defect can be used to isolate the underlying cause. Types of partial anopsia: *Hemianopsia **Homonymous hemianopsia **Heteronymous hemianopsia ***Binasal hemianopsia *** Bitemporal hemianopsia **Superior hemianopia **Inferior hemianopia *Quadrantanopia Quadrantanopia, quadrantanopsia, refers to an anopia (loss of vision) affecting a quarter of the visual field. It can be associated with a lesion of an optic radiation. While quadrantanopia can be caused by lesions in the temporal and parieta ... References External links Visual disturbances and blindness {{eye-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quadrantanopia
Quadrantanopia, quadrantanopsia, refers to an anopia (loss of vision) affecting a quarter of the visual field. It can be associated with a lesion of an optic radiation. While quadrantanopia can be caused by lesions in the temporal and parietal lobes of the brain, it is most commonly associated with lesions in the occipital lobe.Kolb, B & Whishaw, I.Q. Human Neuropsychology, Sixth Edition, p.361; Worth Publishers (2008) Presentation An interesting aspect of quadrantanopia is that there exists a distinct and sharp border between the intact and damaged visual fields, due to an anatomical separation of the quadrants of the visual field. For example, information in the left half of visual field is processed in the right occipital lobe and information in the right half of the visual field is processed in the left occipital lobe. In a quadrantanopia that is partial, there also exists a distinct and sharp border between the intact and damaged field within the quadrant. The sufferer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurology
Neurology (from el, wikt:νεῦρον, νεῦρον (neûron), "string, nerve" and the suffix wikt:-logia, -logia, "study of") is the branch of specialty (medicine), medicine dealing with the diagnosis and treatment of all categories of conditions and disease involving the brain, the spinal cord and the peripheral nerves. Neurological practice relies heavily on the field of neuroscience, the scientific study of the nervous system. A neurologist is a physician specializing in neurology and trained to investigate, diagnose and treat neurological disorders. Neurologists treat a myriad of neurologic conditions, including stroke, seizures, movement disorders such as Parkinson's disease, autoimmune neurologic disorders such as multiple sclerosis, headache disorders like migraine and dementias such as Alzheimer's disease. Neurologists may also be involved in clinical research, clinical trials, and basic research, basic or translational research. While neurology is a nonsurgical sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superior Hemianopia
Superior may refer to: *Superior (hierarchy), something which is higher in a hierarchical structure of any kind Places *Superior (proposed U.S. state), an unsuccessful proposal for the Upper Peninsula of Michigan to form a separate state *Lake Superior, the largest of the North American Great Lakes, Canada, United States United Kingdom * Rickinghall Superior, England United States *Superior, Arizona *Superior, Colorado *Superior, Indiana *Superior, Iowa *Superior Township, Chippewa County, Michigan *Superior Township, Washtenaw County, Michigan *Superior, Montana *Superior, Nebraska *Superior, West Virginia *Superior, Wisconsin, a city *Superior (town), Wisconsin, a town adjacent to the city *Superior (village), Wisconsin, a village adjacent to the city *Superior, Wyoming *Superior (RTA Rapid Transit station), a station on the RTA Red Line in Cleveland, Ohio * Superior Bay, a bay between Minnesota and Wisconsin * Superior Falls, a waterfall between Michigan and Wisconsin Reli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inferior Hemianopia
{{disambiguation ...
Inferior may refer to: * Inferiority complex * An anatomical term of location * Inferior angle of the scapula, in the human skeleton * ''Inferior'' (book), by Angela Saini * ''The Inferior'', a 2007 novel by Peadar Ó Guilín See also *Junior (other) Junior or Juniors may refer to: Arts and entertainment Music * ''Junior'' (Junior Mance album), 1959 * ''Junior'' (Röyksopp album), 2009 * ''Junior'' (Kaki King album), 2010 * ''Junior'' (LaFontaines album), 2019 Films * ''Junior'' (1994 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
