Eye chart number). The denominator indicates the distance in feet at which a person with normal vision could stand to correctly identify the same symbols identified by the person tested. For example, a visual acuity of 20/20 is considered normal. Numerous types of eye charts exist and are used in various situations. For example, the Snellen chart is designed for use at 6 meters or 20 feet, and is thus appropriate for testing distance vision. There is often also a need to test a subject's vision at near or occupational tasks (such as reading or computer use). For these situations, a Rosenbaum
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