8 Position Landolt C chart with C openings at up, down, left, right and each 45º angle. 8 Position Landolt C wall chart is printed on both sides. The front contains proportionally spaced (geometric progression) lines while the backside has 25% linear spaced optotypes. The chart is perfect for vision testing those who maybe illiterate or unfamiliar with letters or numbers optotypes. Both sides have line sizes ranging from 20/100 to 20/8 (6/30 to 6/2.4) equivalent. Hole at top of chart for hanging on the wall. Chart measures 18" x 18" (45.7 cm x 45.7 cm) and folds in half to 18” x 9” (45.7 cm x 22.8 cm) for easy storage. 10 feet, 3 meter testing distance.