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From 1974 until the early-2000s, the map production area was the printing plant for USGS topographic maps and other paper products. The USGS Library, authorized by Congress in 1879, houses one of the world’s largest Earth and natural science collections. [5] The building originally had the capacity to house nearly 2,500 employees. [4]
The USGS Coastal and Marine Science Center (formerly the USGS Center for Coastal Geology) has three sites, one for the Atlantic Ocean (located in Woods Hole, Massachusetts), one for the Pacific Ocean (located in Santa Cruz, California) and one for the Gulf of Mexico (located on the University of South Florida's St. Petersburg campus). The goal ...
Fundus of geographic atrophy. Geographic atrophy (GA), also known as atrophic age-related macular degeneration (AMD) or advanced dry AMD, is an advanced form of age-related macular degeneration that can result in the progressive and irreversible loss of retinal tissue (photoreceptors, retinal pigment epithelium, choriocapillaris) which can lead to a loss of central vision over time.
oculus sinister (left eye) LHyperT or LHT: Left hypertropia LHypoT: Left hypotropia LO: Lenticular opacity L/R FD: L/R fixation disparity L/R: L hyperphoria Left ET: Left esotropia LVA: Low vision aid MDU: Mallett distance unit MNU: Mallett near unit M.Wing: Maddox Wing: MR: Maddox rod NB: NAD: No abnormality detected (is frequently used but is ...
The Amsler grid showing the visual perception of the left eye of a person experiencing metamorphopsia (straight lines appear bent or curved) [1] [2]. Metamorphopsia (from Ancient Greek: μεταμορφοψία, metamorphopsia, 'seeing mutated shapes') is a type of distorted vision in which a grid of straight lines appears wavy or partially blank.
At any given moment, the line of sight of the two eyes meet at a point in space. This point in space projects to the same location (i.e. the center) on the retinae of the two eyes. Because of the different viewpoints observed by the left and right eye however, many other points in space do not fall on corresponding retinal locations.
From 1983-1989, Neal worked for the U.S. Geological Survey at the Hawaiian Volcano Observatory. In 1990, she joined the newly established Alaska Volcano Observatory in Anchorage, Alaska, where she monitored eruptions in the Aleutian Arc and investigated the eruptive history and volcanic hazards along the Alaska Peninsula and eastern Aleutians. [6]
To measure eye movement, pairs of electrodes are typically placed either above and below the eye or to the left and right of the eye. If the eye moves from center position toward one of the two electrodes, this electrode "sees" the positive side of the retina and the opposite electrode "sees" the negative side of the retina.