A Comparative Study of the Sensitivity and Specificity of the Ishihara Test With Various Displays

Abstract

Visual colour differentiation in clinical research requires colour-competent (CC) participants. The Ishihara colour charts (ICC) have established themselves as the standard for CC screening of colour vision deficiencies (CVD). However, the extent to which the results can be compared with a presentation of the colour charts on a smartphone display (SD) is currently unknown. The aim of this in vitro study was to determine the sensitivity and specificity of the Ishihara colour deficiency test depending on the presentation mode. Dental students (female n=28; male n=10; mean age, 23.5 ± 2.65 years; median age, 23.0 ± 13.0 years) evaluated 25 Ishihara test plates on their SD (n=38) and/or a calibrated monitor (HP monitor, 22-inch; n=18). The median size of the SD was 6.0 inches. Datasets with more than 2 failed charts were scored. When the Ishihara test charts were presented on a PC screen, the sensitivity was 94.4% and the specificity was 82.4% (0 mistakes: n=14, <3 failures: n=3, 14 false answers: n=1). On the SD, a sensitivity of 96.0% and a specificity of 94.7% were calculated (89.5% were correct; 4 participants [10.5%] made <3 errors; and 1 participant made 21 errors). No significant difference between display modi (PC vs SD) was evaluated (P > .05). The presentation of ICC on an SD is useful and can be used for the investigation of a possible CVD of large groups. Comparable results to data projection can be achieved with a high degree of certainty. For CVD screening of larger groups (eg, students in preclinical training as part of CC training), the presentation of ICC on the SD can be used. This research was able to demonstrate that the sensitivity and specificity of the usual presentation method (Ishihara's booklet or data projection) is comparable.