Perimetry or campimetry is the systematic measurement of differential light sensitivity in the visual field The term visual field is sometimes used as a synonym to field of view, though they do not designate the same thing. The visual field is the "spatial array of visual sensations available to observation in introspectionist psychological experiments", while 'field of view' "refers to the physical objects and light sources in the by the detection of the presence of test targets on a defined background. Visual field testing can be performed clinically with confrontational field testing keeping the subject's gaze fixed while presenting objects at various places in their visual field. This is generally used to explore the extreme boundaries of the visual field. Perimetry more carefully maps and quantifies the visual field. Simple manual equipment can be used such as in the tangent screen test or the Amsler grid. When dedicated machinery is used it is called a perimeter. Kinetic perimetry uses a mobile stimulus moved by a perimetrist such as in Goldmann kinetic perimetry. Kinetic perimetry is useful for mapping visual field sensitivity boundaries. Threshold static perimetry is generally done using automated equipment. It is used for rapid screening and follow up of diseases involving deficits such as scotomas A scotoma is an area of partial alteration in one's field of vision consisting in a partially diminished or entirely degenerated visual acuity which is surrounded by a field of normal - or relatively well-preserved - vision, loss of peripheral vision Peripheral vision is a part of vision that occurs outside the very center of gaze. There is a broad set of non-central points in the field of view that is included in the notion of peripheral vision. "Far peripheral" vision exists at the edges of the field of view, "mid-peripheral" vision exists in the middle of the field of and more subtle vision loss. Perimetry testing is important in the screening, diagnosing, and monitoring of various eye Eyes are organs that detect light, and convert it to electro-chemical impulses in neurons. The simplest photoreceptors connect light to movement . In higher organisms complex neural pathways exist that connect the eye, via the optic nerve to the visual cortex and other areas of the brain. Complex optical systems with resolving power have come in, retinal The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical events that ultimately trigger nerve impulses. These, optic nerve The optic nerve is the second of twelve paired cranial nerves but is considered to be part of the central nervous system as it is derived from an outpouching of the diencephalon during embryonic development. Consequently, the fibres are covered with myelin produced by oligodendrocytes rather than the Schwann cells of the peripheral nervous system and brain The brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as jellyfish and starfish have a decentralized nervous system without a brain, while sponges lack any nervous system at all. In vertebrates, the brain is located in the head, protected by the skull and close to the primary disorders.

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This eye Eyes are organs that detect light, and convert it to electro-chemical impulses in neurons. The simplest photoreceptors connect light to movement . In higher organisms complex neural pathways exist that connect the eye, via the optic nerve to the visual cortex and other areas of the brain. Complex optical systems with resolving power have come in article is a stub. You can help Wikipedia by expanding it.
This standards Standardization or standardisation is the process of developing and agreeing upon technical standards. A standard is a document that establishes uniform engineering or technical specifications, criteria, methods, processes, or practices. Some standards are mandatory while others are voluntary. Voluntary standards are available if one chooses to- or measurement In science, measurement is the process of estimating or determining the magnitude of a quantity, such as length or mass, relative to a unit of measurement, such as a metre or a kilogram. The term measurement can also be used to refer to a specific result obtained from the measurement process-related article is a stub. You can help Wikipedia by expanding it.

Categories: Ophthalmology Categories: Medical specialties | Surgical specialties | Eye | Vision | Neurology Categories: Medical specialties | Nervous system | Neuroscience |

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No Line on the Horizon is the twelfth studio album by the rock band U2. Released on 27 February 2009, it was the group's first album since How to Dismantle an Atomic Bomb , marking the longest gap between studio albums of U2's career. Work on the record began in 2006 with producer Rick Rubin, but most of the material from those sessions was
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