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
Letters of the Living is 19. The word Wáḥid means "One". The Báb used this term as a reference to God and his Manifestations. The Letters are listed here in the order given by Nabíl in The Dawn-Breakers, and supported by Qatíl al-Karbalá'í except where indicated: Muḥammad-Ḥasan Bushrú'í was the second Letter of the Living, and the brother of Mullá Husayn. He, his sons, Muḥammad-Báqir Bushrú'í, and Mullá Ḥusayn travelled to Shiraz in search of the Qá'im; where the Báb revealed his message. He was killed during the Battle of Fort Tabarsi. Bábís consider him a martyr. Muḥammad-Báqir Bushrú'í was the third Letter of