D15

Significance: The Lanthony D15 has been reported to have poorer repeatability than the Farnsworth D15. This study found that two trials of the test provide high short-term repeatability and can be administered this way for occupational testing. Purpose: This study aimed to determine the short-term repeatability of the Lanthony D15 in patients with color vision deficiency. Repeated trials were used to examine if learning effects occur and to determine how many trials would be necessary to ensure the highest short-term repeatability for occupational testing. Methods: Twenty male subjects (mean [standard deviation] age, 27.2 [4.3] years) with congenital color vision deficiency, ranging from mild to severe, participated in this single-visit study. Visual acuity, color vision book screening, Farnsworth D15, and anomaloscope testing were performed for classification purposes. Ten trials of the Lanthony D15 were performed. Color confusion index scores from each trial were determined, and a repeated-measures analysis of variance was used to compare the scores across trials. Orthogonal polynomial analysis was performed to detect any trends across trials through the third order. The intraclass correlation coefficient was calculated. Results: No differences in color confusion index (mean [standard error of the mean], 3.57 [0.04]) were found across the 10 trials ( P = .18). Legendre polynomials showed no statistical significance (all P > .39). The intraclass correlation coefficient was 0.81 (95% confidence interval, 0.70 to 0.90). Based on the method of Shrout and Fleiss, intraclass correlation coefficients of 0.7, 0.8, and 0.9 could be achieved with an average of one, two, and four trials of the test, respectively. However, empirically, 0.9 was not achievable. Conclusions: The Lanthony D15 test has fairly high short-term repeatability. Thus, although more trials would likely improve clinical certainty, the mean result of two trials appears sufficient for occupational testing.

This study determined the AC1 agreement values between computer-based color vision tests and the Farnworth-Munsell D-15 (F-D15) and the Holmes-Wright Type A lantern (HWA). The computer-based tests were the United States Air Force Cone Contrast Test (OCCT), Cambridge Color Test, Innova Rabin Cone Contrast, Konan-Waggoner D15 (KWC-D15), and Color Assessment and Diagnosis (CAD). Sixty-eight color-vision-defective persons participated. The KWC-D15 had the highest AC1 with the F-D15 (${\rm AC1} = {0.88}$AC1=0.88). Both the CAD and OCCT had the highest values with the HWA (${\rm AC1} \gt {0.96}$AC1>0.96). The KWC-D15 would be the best substitute for the F-D15. Either the CAD or OCCT would be appropriate substitutes for the HWA.

The W-D15 test, a computerized variant of the F-D15 test, is used to determine whether an individual with a color vision defect can safely perform color-related tasks. This study evaluated the performance of the W-D15 test using an iPad. Fifty-nine color normal and 61 color vision defect subjects participated. Participants were screened based on the Ishihara, City University Test, and Waggoner PIP24 tests. Different failure criteria of the D15 tests were considered. The pass/failure agreement between the two tests was relatively appropriate, with a κ-coefficient ≥0.8, for all failure criteria. The W-D15 could be an appropriate substitute for F-D15 using an iPad.