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 their friend, time-travelling alien the Doctor (Matt Smith), to come the planet Trenzalore, the site of the Doctor's future grave. The Intelligence attempts to force the Doctor to open a door leading to his time stream, which the Intelligence intends to interfere with to undo all of his victories. "She Said, He Said" is a mini-episode that acts as a prelude to "The Name of the Doctor", in which the Doctor and Clara each have a monologue about how little they know about each other and that they discovered each other's secret at Trenzalore. It was released on on BBC