Eye chart smaller towards the bottom of the chart. The person removes any glasses or contact lenses, and stands or sits a standardized distance from the chart (e.g., 20 feet for the Snellen chart). The person is then asked to identify the optotypes on the chart, starting with large rows and continuing to smaller rows until the optotypes cannot be reliably identified any more. The row in which the person can reliably identify symbols defines the visual acuity. One eye is tested at a time. Practically, this is accomplished by covering the other eye with a hand, piece of paper, or a
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