A Sloan Letter ETDRS contrast chart with 2.5% contrast and proportionally spaced (logMAR) lines; line sizes range from 13/131 to 13/6.5 (20/200 to 20/10 equivalent) with Letter size, 4 meter, 6 meter, LogMar, 10 feet, and decimal notations. These charts fit in the ESV3000 ETDRS Standardized Viewer and ESC2000 Illuminated Cabinet.
Testing distance: 13 feet/4 meters.