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
Superior letter o, r, s, and t. In English, however, 'h' is also sometimes rendered as a superior letter, as in 6th. In French, certain abbreviations are written with the first letter(s) of the word they represent, followed by the final letter(s) in superscript. The superscript in this case is sometimes optional. Most commonly, this appears in the abbreviations of personal titles: "M" (or "Mgr") stands for "monseigneur" ("Your Grace"), "M" (or "Mlle") for "mademoiselle" ("Miss"), "M" for "maître" ("Mr"), etc. Other abbreviations containing superior letters are "m" for "merchandise" ("merchandise"), "éch" for "échéance" ("due date"), and "M" for "métro" ("subway"). When