This "revised" eye chart incorporates a slight change in the difficulty score for each of the ten SLOAN letters derived from the best correted visual acuity examinations of 7,420 eyes during the ETDRS study.
For vision testing at 2 meters (6.5 ft.)
Acuity range 20M to 1M (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
Unlike a traditional Snellen chart, ETDRS charts use the same amount of optotypes on each line. This organization of optotypes helps prevent mistaken gain and loss of lines while testing over lengths of time. Furthermore, ETDRS charts use equality from optotype to optotype and line to line making the acuity chart balanced.
IS
