Designed to measure visual acuity with a standard line test and with
three tighter spaced tests; 50%, 25% and 12.5% which often reveal
difficulties in seeing tightly crowded details. Line sizes range from
20/400 to 20/10 (6/120 to 6/3) equivalent, 0.05 to 2.00. Card measures
8" x 10" (20.3 cm x 25.4 cm).