Table 1.

Summary of the cone pigment genes and the corresponding spectral separation (δλ_max) in the group of 15 subjects with deutan-like deficiency investigated in this study. The first column indicates the sequence of cone pigment genes in the array as determined genetically. Note that with the exception of the first four subjects that have only one L cone pigment gene in the array and are therefore deuteranopes, the remaining color deficient subjects rely on both normal and variant L cone pigment genes. These provide a wavelength separation in the range 2.5 to 10 nm. The corresponding optical densities of the variant and the normal L-cone genes are indicated as OD(L’ ) and OD(L). Other parameters such as the equivalent Nagel range, RGI (red-green discrimination index) and red-green and yellow-blue CAD thresholds are also given. The Nagel model predicts well the mid point of each match for the corresponding, non-zero δλ_max value by appropriate adjustment of cone pigment optical densities and selection of equivalent Nagel range. The latter is defined as the Nagel range the subject would have if no color deficiency was involved and the δλ_max corresponded to the expected value in normal trichromats. Interestingly, we were unable to predict the Nagel range measured experimentally with any combination of selected parameters for one of the four deuteranopes (second entry in the table, Nagel range: 3 to 52 units). The model does, however, predict accurately the measured range for the parameters shown in the table, provided one assumes a wavelength separation of 2.5 and not zero nm, as predicted from genetics (see Results section for possible explanations for this finding). The RGI is defined as 1-(R-MR)/73, where R is the subject’s range and MR is the mean matching range estimated in 67 normal trichromats. The CAD unit is the median threshold value estimated from data measured in 250 normal trichromats. The red-green and yellow-blue chromatic detection thresholds are expressed in CAD units and the reciprocal of these thresholds provide a measure of chromatic sensitivity. The use of RGI and reciprocal CAD units makes it convenient to compare different measures of chromatic sensitivity

#L, #M genes	Predicted phenotype	Derived δλmax	Nagel	RGI	OD(L’)	OD(L)	Equiv. Nagel range	Red-Green (CAD units)	Yellow-Blue (CAD units)
1L, 0M	deuteranope	0	0–50	0.37	0.415	0.5	4	24.9	1.2
1L, 0M	deuteranope	0 (2.5?)	3–52	0.37	0.32	0.21	2.2	23.5	0.9
1L, 0M	deuteranope	0	0–48	0.37	0.405	0.495	4	21.9	l.l
1L, 0M	deuteranope	0	0–56	0.27	0.415	0.49	4	17.6	1.0
3L, 2M	deutan	2.5–0	8–33	0.76	0.425	0.335	1.4	15.1	0.8
2L, 1M	deutan	2.5	0–28	0.67	0.5	0.52	4	13.5	1.3
2L, 2M	deutan	2.5	0–37	0.53	0.5	0.5	5.2	12.2	0.9
2L, 2M	deutan	2.5	0–8	0.94	0.35	0.7	2	17.4	0.8
2L, 2M	deutan	2.5	2–31	0.70	0.27	0.245	2.2	13.6	1.4
2L, 1M	deutan	6–3.5	11–14	0.99	0.28	0.51	1.2	2.8	0.9
2L, 3M	deutan	6	8–15	0.94	0.3	0.57	2.2	3.3	1.0
2L, 1M	deutan	6	14–23	0.94	0.32	0.335	2.4	2.9	0.8
2L, 0M	deutan	6.5	15–18	0.99	0.56	0.46	1	2.6	0.8
2L, 1M	deutan	10	15–17	1.00	0.5	0.61	1	2.0	1.2
2L, 1M	deutan	10	15–18	1.00	0.5	0.59	1.2	2.6	1.0
1L, 1M	normal	28	38–42	1.00	0.5	0.5	4	1	1