The first part of the eye exam is an assessment of acuity. This can be done with either a standard Snellen hanging wall chart read with the patient standing at a distance of 20 feet or a specially designed pocket card (held at 14 inches). Each eye is tested independently (i.e. one is covered while the other is used to read). The patient should be allowed to wear their glasses and the results are referred to as "Best corrected vision." You do not need to assess their ability to read every line on the chart. If they have no complaints, rapidly skip down to the smaller characters. The numbers at the end of the line provide an indication of the patient's acuity compared with normal subjects. The larger the denominator, the worse the acuity. 20/200, for example, means that they can see at 20 feet what a normal individual can at 200 feet (i.e. their vision is pretty lousy). If the patient is unable to read any of the lines, indicative of a big problem if this was a new complaint, a gross estimate of what they are capable of seeing should be determined (e.g. ability to detect light, motion or number of fingers placed in front of them). In general, acuity is only tested when there is a new, specific, visual complaint.