Snellen chart H, K, O, S, 3, U, Y, A, C, E, G, L, 2. The normal Snellen chart is printed with eleven lines of block letters. The first line consists of one very large letter, which may be one of several letters, for example E, H, or N. Subsequent rows have increasing numbers of letters that decrease in size. A person taking the test covers one eye from 6 metres or 20 feet away, and reads aloud the letters of each row, beginning at the top. The smallest row that can be read accurately indicates the visual acuity in that specific
About the Mystery of the Letters Father respectively. The final chapters of the treatise engage in speculation about more general topics, including the history of mankind – whose key events are related symbolically to the sequence of vowels and consonants in the alphabet –, a discussion of Christology dealing with issues related to the Council of Chalcedon, and reflections upon the name of "Adam". About the Mystery of the Letters About the Mystery of the Letters (, "Peri tou mystēriou tōn grammatōn") is an anonymous Christian treatise containing a mystical doctrine about the names and forms of the Greek and Hebrew letters. It was probably written