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
The Name of the Doctor of which, subtitled "The Name of the Doctor", Strax informed the Sontarans of a great battle predicted to occur and admitting suspicions that it had to do with the Doctor's greatest secret. He informed Sontar that the operation was called "The Name of the Doctor". In the second, subtitled "A Glorious Day Is Almost Upon Us...", Strax discussed a 'glorious day' in which death was likely. The final field report — "The Doctor's Greatest Secret" — discussed the cliffhanger, commenting that this new Doctor had the appearance of a warrior. This was the only field report released after the episode.