Amsler grid Amsler grid The Amsler grid, used since 1945, is a grid of horizontal and vertical lines used to monitor a person's central visual field. The grid was developed by Marc Amsler, a Swiss ophthalmologist. It is a diagnostic tool that aids in the detection of visual disturbances caused by changes in the retina, particularly the macula (e.g. macular degeneration, Epiretinal membrane), as well as the optic nerve and the visual pathway to the brain. In the test, the person looks with each eye separately at the small dot in the center of the grid. Patients with macular disease may see
Military Grid Reference System Military Grid Reference System The Military Grid Reference System (MGRS) is the geocoordinate standard used by NATO militaries for locating points on the earth. The MGRS is derived from the Universal Transverse Mercator (UTM) grid system and the universal polar stereographic (UPS) grid system, but uses a different labeling convention. The MGRS is used for the entire earth. An example of an "MGRS coordinate", or "grid reference", would be [21_18_34.0_N_157_55_0.7_W_&language=en 4QFJ12345678], which consists of three parts: An MGRS grid reference is a point reference system. When the term 'grid square' is used, it can refer to a square with a