For vision 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.)
Only standardized format accepted in studies sponsored by the National Eye Institute
Designed for use in clinical studies and low vision evaluations where accurate, repeatable visual acuity measurements are required
Lines are of equal difficulty
Geometric progression in letter size from line to line
Letter size is only variable
Measures 62 X 65 cm (24.5 X 25.5 in.)
Eye Chart fits the ETDRS Illuminator Cabinet CAT. NO. 2425
Can be wall-mounted
ETDRS style vision tests use 10 calibrated, equally difficult Sloan optotypes in the chart. These optotypes are used five per line and are arranged to where each line has equal difficulty scores. Also the optotypes are organized so no words are spelled in the chart. This helps to reduce undesired hints during the vision exam.
IS
