For testing at 2.5 meters (8.3 ft.)
Acuity range 25.2M to 1.2M (20/200, 6/60 to 20/10, 6/3 equiv.)
Measures 62 X 65 cm (24.5 X 25.5 in.)
Fits ETDRS Illuminator Cabinet CAT. NO. 2425
Can also be wall mounted
This "revised" chart incorporates a slight change in the difficulty score for each of the ten SLOAN letters derived from the best corrected visual acuity examinations of 7,420 eyes during the ETDRS study. The "original charts" difficulty scores were derived from the examination of 234 eyes. In addition to the "revised" arrangement of letters which resulted in the ultimate homogeneity of difficulty per line, the three charts (Chart 1, 2, and 3) are balanced so that in each chart the ten SLOAN letters are represented at least once in every position.