Description
ETDRS charts use a series of three charts with different permutations of optotypes. ETDRS "Chart 1" is used to test the right eye's acuity. ETDRS "Chart 2," and "Chart R" are used to test the visual acuity in the left eye and both eyes, respectively. The use of three ETDRS eye charts to test the visual acuity of one patient prevents memorization and helps increase accuracy and consistency in results.