MEASUREMENT OF VISUAL-ACUITY WITH 2 DIFFERENT CHARTS - A COMPARISON OF RESULTS AND REPEATABILITY IN PATIENTS WITH CATARACT

Purpose: To compare two different optotypes to measure visual acuity. Methods: Experiment 1: Fifty patients with moderate cataracts were ask ed to read a chart consisting of letters of the alphabet (Sloan letter s) first and a chart comprising Landolt's broken rings afterwards. Exp eriment 2: Half of patients were instructed to repeat the reading with a second letter chart, the other half was instructed to read the char t with the broken rings again. Results and conclusions: Experiment 1: It was found that with the letter chart more optotypes (two to four) w ere recognized than with the broken ring chart. The different result o f visual acuity measurement with the two optotypes is irrespective of the visual acuity. Experiment 2: The re-read instruction revealed that the measurements were reproduced equally for both charts.