LeGrand H. Hardy, Gertrude Rand, and M. Catherine Rittler, "Tests for the Detection and Analysis of Color-Blindness. I. The Ishihara Test: An Evaluation," J. Opt. Soc. Am. 35, 268-275 (1945)
The Ishihara test for color-blindness, taken as a representative type of polychromatic tests, fails to give more than a superficial evaluation of the state of an observer’s color vision. It can be utilized as a good rough screening test for red-green color blindness, but in so doing most of the plates could be discarded. The results obtained are dependent to a large extent upon the illuminant used, and this fact militates against the deuteranomalous observer. The test gives neither an adequate qualitative (type of defect) nor quantitative (extent of defect) diagnosis, and may give a wrong diagnosis. Results obtained by this test should be discounted unless verified by other modern types of tests.
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Analysis of individual plates. Percentage of each type of color defective subject and of the low normals passing each plate of the Ishihara test, fifth edition.
Percentage of each type passing individual plates
Series no.
1
2
3
4
5
6
Plate no.
Type of color defective subject
Number of cases
2
3
4
5
6
7
8
9
10
11
12
13
Anomalous trichromat
%
%
%
%
%
%
%
%
%
%
%
%
deuteranomalous
23
43
43
0
0
13
22
17
39
13
0
17
30
protanomalous
12
67
67
0
0
0
0
8
8
0
0
8
17
Dichromat
deuteranope
15
0
7
0
0
0
0
0
0
0
0
0
0
protanope
17
53
59
0
0
0
0
0
0
24
18
0
0
Low discrimination
7
57
71
0
0
14
57
14
43
0
0
43
86
All color defectives
74
42
46
0
0
5
12
8
18
9
4
11
20
Low normals
32
100
100
100
78
87
100
100
94
87
84
97
97
Table II
Significance of performance score. Showing for each type of color defective subject and for the low normals (a) the average performance score achieved by each group; (b) the median or middle score for each group; and (c) the range of scores from lowest to highest achieved by the individuals within each group. Performance score is percentage of the 12 plates to which correct responses were given.
Type of color defective subject
Number of cases
Average score
Median score
Range of scores
Anomalous trichromat
deuteranomalous
23
20
17
0–58
protanomalous
12
15
17
0–33
Dichromat
deuteranope
15
1
0
0–8
protanope
17
13
17
0–33
Low discrimination
7
31
25
8–58
All color defectives
74
15
13
0–58
Low normals
32
94
100
75–100
Table III
Distribution of performance scores. Percentage of each type of color defective subject and of the low normals having different ranges of performance score on Ishihara test (fifth edition).
In this group, 53 percent passed all 12 plates (scored 100), 22 percent passed 11 plates (scored 92), 22 percent passed 10 plates (scored 83), and 3 percent passed 9 plates (scored 75).
Table IV
Differential classification of deuteranopia and protanopia. Analysis of the value of Plates 12 and 13 (Series 6) as a means of differentiating between deuteranopic and protanopic types of red-green defective subjects.
Percentage of cases correctly diagnosed by
Percentage of cases incorrectly diagnosed by
Percentage of cases not diagnosed by
Type of color defective subject
Number of cases
Plate
Both plates
Either plate
Plate
Both plates
Either plate
Plate
Both plates
Either plate
12
13
12
13
12
13
Anomalous trichromat
%
%
%
%
%
%
%
%
%
%
%
%
deuteranomalous
23
65
65
57
74
0
0
0
0
35
35
43
26
protanomalous
12
50
83
50
83
8
0
0
8
42
17
50
8
Dichromat
deuteranope
15
93
93
87
100
0
0
0
0
7
7
13
0
protanope
17
41
59
29
71
6
6
6
6
53
35
65
23
Tables (4)
Table I
Analysis of individual plates. Percentage of each type of color defective subject and of the low normals passing each plate of the Ishihara test, fifth edition.
Percentage of each type passing individual plates
Series no.
1
2
3
4
5
6
Plate no.
Type of color defective subject
Number of cases
2
3
4
5
6
7
8
9
10
11
12
13
Anomalous trichromat
%
%
%
%
%
%
%
%
%
%
%
%
deuteranomalous
23
43
43
0
0
13
22
17
39
13
0
17
30
protanomalous
12
67
67
0
0
0
0
8
8
0
0
8
17
Dichromat
deuteranope
15
0
7
0
0
0
0
0
0
0
0
0
0
protanope
17
53
59
0
0
0
0
0
0
24
18
0
0
Low discrimination
7
57
71
0
0
14
57
14
43
0
0
43
86
All color defectives
74
42
46
0
0
5
12
8
18
9
4
11
20
Low normals
32
100
100
100
78
87
100
100
94
87
84
97
97
Table II
Significance of performance score. Showing for each type of color defective subject and for the low normals (a) the average performance score achieved by each group; (b) the median or middle score for each group; and (c) the range of scores from lowest to highest achieved by the individuals within each group. Performance score is percentage of the 12 plates to which correct responses were given.
Type of color defective subject
Number of cases
Average score
Median score
Range of scores
Anomalous trichromat
deuteranomalous
23
20
17
0–58
protanomalous
12
15
17
0–33
Dichromat
deuteranope
15
1
0
0–8
protanope
17
13
17
0–33
Low discrimination
7
31
25
8–58
All color defectives
74
15
13
0–58
Low normals
32
94
100
75–100
Table III
Distribution of performance scores. Percentage of each type of color defective subject and of the low normals having different ranges of performance score on Ishihara test (fifth edition).
In this group, 53 percent passed all 12 plates (scored 100), 22 percent passed 11 plates (scored 92), 22 percent passed 10 plates (scored 83), and 3 percent passed 9 plates (scored 75).
Table IV
Differential classification of deuteranopia and protanopia. Analysis of the value of Plates 12 and 13 (Series 6) as a means of differentiating between deuteranopic and protanopic types of red-green defective subjects.