Eye chart smaller symbols until the person cannot identify the symbols. The smallest symbols that can be reliably identified is considered the person's visual acuity. The Snellen chart is the most widely used. Alternative types of eye charts include the logMAR chart, Landolt C, E chart, Lea test, Golovin–Sivtsev table, the Rosenbaum chart, and the Jaeger chart. Charts display several rows of optotypes, which are standardized symbols for testing vision. Optotypes are usually letters, numbers, or geometric symbols. Each row of the chart depicts optotypes of a different size. Typically the largest optotypes are in the top row. The optotypes become progressively
The 13th Letter The 13th Letter The 13th Letter is a 1951 American film noir mystery film directed by Otto Preminger. The film is a remake of the French film "Le Corbeau" ("The Raven", 1943) directed by Henri-Georges Clouzot. Doctor Pearson (Michael Rennie), who works at a Canadian hospital in the province of Quebec, receives a series of poison pen letters. More letters, all signed with the mysterious picture of a feather, are delivered to others in the small Canadian town. Cora Laurent (Constance Smith), the wife of the main doctor - Dr. Laurent (Charles Boyer) - at the hospital, receives a letter