Eye chart chart or Jaeger chart can be used. While the Snellen chart remains the default, some authors have argued that the logMAR chart is superior. The logMAR chart presents the same number of symbols on each line, uses a typeface with letters that are equally legible at various sizes, and by varying the symbol size logarithmically, it is easier to use at nonstandard distances. As a consequence of these improvements, the logMAR chart has been proposed as a more reliable tool for measuring visual acuity. However, the logMAR chart has not yet been widely adopted. It can be difficult to measure
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