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
Grid fin The grid fin development effort is a part of the SpaceX reusable launch system development program that has been underway since 2012. The first hypersonic flight test with grid fins was in February 2015, and grid fins were subsequently used on all reusable Falcon 9 experimental test landings and, eventually, after December 2015, an increasing number of successful first stage landings and recoveries. Iteration on the design of the Falcon 9 grid fins continued into 2017. SpaceX CEO Elon Musk announced in early 2017 that a new version of the Falcon 9 grid fins would improve reusability for the company's