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 to kill the Doctor's allies unless the Doctor says his name to unlock the TARDIS doors. The Doctor refuses, but as he speaks, River says the Doctor's name and unlocks the TARDIS. Inside, the Doctor reveals a pulsating column of light to be his time stream. The Great Intelligence enters it in order to undo the Doctor's past as revenge for all the defeats it has been dealt. The positive effects of the Doctor's travels begin to be nullified by the Intelligence's interference. Jenny and Strax both disappear. Clara remembers the Doctor telling her that she has helped the Doctor