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 Name of the Doctor" received overnight ratings of 5.46 million viewers on BBC One. When viewers who watched the episode later on were taken into account, the figure rose to 7.45 million, making "Doctor Who" the third most-watched programme of the week on BBC One. The episode received an Appreciation Index of 88. The episode received positive reviews. Mark Snow of IGN gave the episode 9.1/10, praising the final conversation between the Doctor and River Song, as well as the revelation about Clara; however he noted that the Great Intelligence was "a little underwhelming" and "not very threatening", and that