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Purpose: For the purpose of classification for social adaptability of color vision defectiveness, the Farnsworth Dichotomous Test D-15(Test D-15)was applied to distinguish a severe group from other cases. Following this, the Ichikawa Lantern was employed to separate a moderate from a mild group. Majima's classification has provided a convenient framework for identifying color vision defectiveness for the past several decades. However because of the discontinuity in the employment of Ichikawa's Lantern, the introduction of alternative methods is vital. New classification methods subdividing the "moderate/mild" group into separate groups were established by using simulations. Subjects and methods: Simulations of hue discrimination using the color caps of Test D-15 were carried out. Adding color caps one by one between each of the 15 color test caps of Test D-15 to a total of 30, or subtracting caps from Test D-15 to nine (P-1-3-5-7-9-11-13-15)or six(P-2-5-8-11-14) were employed to simulate the compressing of the hue circles along the color confusion lines. Simulations changing the saturation of color caps were conducted simultaneously. Results: The fewer the number of caps, the more errors occurred. Subtracting the number of caps of Test D-15 made it possible to subdivide the "moderate/mild" group into three groups. Changing the saturation of color caps of Test D-15 had no effect on the results of the Test D-15. Conclusion: Using Test D-15 and reducing the number of caps to nine or six allows for the identification of different levels of color defectiveness and the assigning of patients into separate groups.

Compare to either the middle or the long cones, short cones (S-cone) are easily damaged.A 62 year-old men complained of acute tritan OS. The corrected visual acuity was 1.2 OU. Routine ocular examinations showed no remarkable abnormalities, but we detected impaired responses using S-cone ERG and blue-on-yellow perimetry OS. We diagnosed this case as acute damage of the blue cone.S-cone damage can be determined by electro-physiological and psychophysical examinations in cases of unilateral color abnormality.

(1) Human crystalline lens and vision In order to investigate the hue changes in eyes with UV-absorbing intraocular lenses (IOLs) and tinted IOLs, we simulated the changes in the chromaticity coordinates of the 16 colors of the Farnsworth dichotomous test-panel D-15 (panel D-15), considering the ratio of the spectral transmittance of the IOL and the human crystalline lens, and the results were plotted on a CIE chromaticity diagram. The chromaticity coordinates of each color for UV-absorbing IOLs shifted to close to the origin of coordinates while retaining their hue circle. However, the chromaticity coordinates for the eyes with tinted IOLs did not change much compared to the coordinates for phakic eyes. As a result, it was suggested that cyanopsia after UV-absorbing IOL implantation could be explained by this simulation. As far as the color perception is concerned, it was also felt that tinted IOLs were superior to UV-absorbing intraocular lenses. Next, in order to evaluate the hue changes after IOL implantation, the achromatic point settings were measured once before surgery and several times at intervals after surgery after taking off the eyepatch. Four subjects participated in the experiments. There was a large shift into the "yellowish" region of color space immediately after taking off the eyepatch after cataract surgery. Then, the achromatic point returned to the chromaticity near the achromaticpoint measured prior to the surgery, with the time course of a long time, compared to color constancy in our daily life, which takes as long as several hundreds of seconds to reach an asymptote. Therefore, the mechanism of achromatic point shifts after cataract surgery may be different from the color-constancy mechanism in everyday life. (2) Molecular genetics and vision We demonstrated new clinical and genetic aspects of congenital red-green color vision defects, congenital achromatopsia, enhanced s-cone syndrome (ESCS), and Oguchi disease in Japanese patients. We clinically diagnosed 88 male dichromats(31 protanopes, 56 deuteranopes, and one unclassified subject). This subject had a new form of X-linked pigment gene with a unique arrangement of exon 5(Y277 from the long-wavelength-sensitive gene and A 285 from the middle-wavelength-sensitive gene). Mutational analysis of patients with achromatopsia disclosed CNGA3 mutations (p.R 436 W, p.L633 P) in one of 14 patients, suggesting low frequency (7%, 1/14) of CNGA3 mutations in the Japanese population. Three novel NR2E3 mutations (p.R 104 Q, p.R 334 G, p.Q 350 X) were identified in both mild and severe forms of ESCS. A novel homozygous GRK1 mutation (p.P 391 H) was found in the Oguchi disease patient with reduced cone responses. This is the first reported Japanese patient with GRK1 -associated Oguchi disease. 3. Information processing of the visual cortex and vision Regarding information processing in the visual cortex, we developed the stimulus to improve identifying retinotopy of the human visual cortex. We performed two types of fMRI experiments. One provided a quick method of mapping retinotopy using a composite stimulus with both ring- and wedge-shaped stimuli. The other provided a method which can show the horizontal meridian clearer. We explored the activation of the visual cortex associated with color perception. In our studies of the color center, we first researched the symptoms and lesions of cerebral achromatopsia, and we next performed the fMRI experiments with a pseudoisochromatic plate test and with a color arrangement test. After this we also performed the fMRI experiments with a complex color painting. We realized objective perimetry with functional brain images. We first developed the software to depict a visual field from the signals of MR imaging. Next we performed the experiment with hemifield stimulation and showed the possibility of its clinical application. Then we showed its reproducibility, performing the experiment with more complicated letter-shaped masked visual stimulation. Finally, we applied the technique to patients with cerebral dysfunction. We performed diffusion tensor imaging (DTI) with a clinical 1.5 T MR machine to visualize optic radiation. With patients who were clinically expected to show disorder of optic radiation, these visualizations were consistent with their pathologies. It was suggested that this new DTI technique is useful for estimating functional disorder of optic radiation.

To determine X-linked red/green visual pigment gene arrays of a female proband with protan deficiency.We examined a brother and both parents as well as the proband. Severity, severe or mild form, of color vision deficiency was estimated with either failure or passing of the Farnsworth Panel D-15 test. Diagnosis of either anomalous trichromacy or dichromacy was performed using a Nagel Type I anomaloscope. Genotypes of red/green visual pigment genes were determined by quantitative polymerase chain reaction-single strand conformation polymorphism analysis.Color vision tests revealed that the proband, her brother, her father, and her mother had protanomaly(mild form), protanopia, protanomaly(severe form), and normal color vision, respectively. In analysis of gene arrays, the brother had a red-green hybrid gene(R1G2, Ser 180) and three green visual pigment genes, while the father had a red-green hybrid gene(R4G5, Ser 180) and a green visual pigment gene.It is impossible to directly determine each paternal or maternal X-linked red/green pigment gene array in the female proband. Molecular analysis of the family members revealed that the proband was a compound heterozygote for two R1 G2 and R4G5 hybrid genes encoding photopigments with different absorption maxima.

Purpose To localize the lesions associated with cerebral achromatopsia. Methods We examined 20 patients with homonymous hemianopsia caused by cerebral infarction(17 men and 3 women aged 49 to 81 years; mean age, 65.1 years). Ishihara plates, standard pseudoisochromatic plates(part 2) and the panel D-15 test were used to examine color perception. Color matching tasks and color naming tasks were used to test color recognition. We tried to apply functional magnetic resonance imaging(fMRI) to lesion analysis in the brain. Results Cerebral achromatopsia was diagnosed in four patients. The analysis showed that lesions in the infracalcarine area(Brodmann's area 18 and 19) were associated with cerebral achromatopsia. Additionally, the lesions associated with failure of the panel D-15(PD-15) test were located more anterior than the lesions associated with failure of Ishihara plates. Conclusion We show evidence that lesions in the anterio-ventral temporo-occipital area are associated with cerebral achromatopsia. This result is in accord with past observations(autopsy, fMRI and positron emission tomography).

I studied two genetic diseases, retinitis pigmentosa (RP) and color vision anomaly, in Kamigoto, one of the off-shore islands in Nagasaki Prefecture. The Prevalance of RP patients in this island was estimated to be one in 473 persons. Among the RP patients observed, familial cases whose disorders are transmitted through successive generations comprised 25.7%. Although it seems that the inheritance mode of RP in these familial cases is autosomal dominant, an autosomal recessive fashion showing quasi-dominance cannot be ruled out, because inbreeding frequently occurs on this island. There were at least two types of RP, one with late onset (40 years of age or later) and the other with early onset, and patients with the latter RP tended to have a poor prognosis. Only a few RP patients had posterior subcapsular cataract, and none had pseudexfoliation in spite of advanced age. Color vision anomalies were found in 3.86% of high-school boys and in 0.41% of girls in this island, and they included protanopia (4.2%), protanomaly (10.4%), deuteranopia (37.5%), and deuteranomaly (47.9%). The prevalence in boys was comparable to that in the general Japanese population, but the prevalence in girls was higher in Kamigoto than in other districts. It is most likely that the unique findings regarding the two disorders reflect geographical and/or social features in Kamigoto island.

I analysed the misnamed colors reported previously by plotting them on the value and chroma diagram. The study included at least 3 subjects for protanopia and at least 5 subjects for deutanopia on the same misnomer applied to one test color. The test colors were expressed by the Munsell color notation system. Deutanopia: High lightness value group (value 5 or more); Gr and lightly saturated G--pink (test color--misnomer), intermediately saturated YR and Y--yellowish green, GY--skin color, highly saturated GY--orange, RP--grey in wide range, lightly or intermediately saturated BG--grey in many cases. Low lightness value group (value 4 or less); Gr--green, lightly saturated Br--green, intermediately saturated YR, GY, G and RP--red, highly saturated R--brown, YR--green, intermediately saturated BG and B--purple, intermediately saturated PB and P--blue. Protanopia: RP--red, PB--purple, P--pink, low lightness value lightly saturated BG--black (this pattern was different from deutanopia), GY--skin color (this pattern was shifted to the lightly saturated area), YR, Y--green (more frequent in protanopia). YR, Y--yellowgreen (more frequent in deutanopia). On the warm color side low sensitivity was anticipated not only for R but also for YR, Y, and GY. This anticipation will be substantiated by increasing the test subjects.

The test colors misnamed were grouped into two in their collation, i.e., R-G and BG-RP. Isochromatic collation was found in 75% of the subjects with normal color vision, 38.3% of those with protanopia, and 33% of those with deutanopia. In the hue collation isochromatic collation was seen most frequently, followed by neighborhood color collation. The more the misnomers, the further separated the hue collation, then the misnaming territory enlarged crossing over the achromatic confusion line, and the collation territory enlarged. The lightness collation was about equal between subjects with abnormal color vision and normal subjects. The former were inferior to the latter by 2% (deutan) and 4% (protan) in isosaturation collation. When the misnomer crossed the isochromatic line or collated near the white point, the date were analysed according to the color cunfusion theory. The subjects with abnormal color vision showed hue collation inferior to that of normal subjects, but they responded with twice the accuracy in the isochromatic collation than the misnomer collation, and the collation territory was narrow and simple.

I report the hue and the color misnomers of 16 subjects with protanopia (color misnomers: 500) and 66 subjects of deutanopia (color misnomers: 2,056), and the color misnomers used by over 10 subjects each and their numbers. Green was the most frequent misnomer, followed by grey, yellow-green, purple, and brown. The deutanopia patients frequently used the Munsell color notation RP for grey. Many of the subjects who misnamed 11 times or more failed the Panel D-15 test. They were diagnosed as having strong color anomaly in the Ohkuma isochromatic plates and in the Tokyo Medical College isochromatic plates. The misnomers were most frequent among the neighboring hues. The severer the anomaly, the further the separation from the test color, and then the misnomers crossed the achromatic confusion line. Judging from the misnomer variation, the color sense of color anomaly does not necessarily seem to be constant. Moreover, liaison was noticed among red, brown, green, or occasionally purple in terms of misnaming pattern. Grey and pink were also linked in misnaming. Lightness was considered to play a strong role in these confusions.

We evaluated the panel D-15 test under reduced illumination in subjects with color vision deficiency and in normal subjects. Forty subjects with color vision deficiency (3 protanopes, 10 protanomalies, 10 deuteranopes, 7 extreme deuteranomalies and 10 deuteranomalies) and 10 normal subjects were the subjects for the experiment. Seven light levels ranging from 0.9 to 900 lux were used. All normal subjects passed the test at 3.5 lux or more and 30% failed at 0.9 lux. Color vision defective subjects began to fail the test at 225 lux, with 56% failing at 3.5 lux and 92% at 0.9 lux. The performance on the panel D-15 test decreased in proportion to decreasing the illumination in some color vision defective subjects. Some protanomalous subjects showed a deutan pattern at low illumination levels.

Color vision standards for various occupations and schools have been greatly eased recently. However, if the trend is unaccompanied with proper advice for color defective persons, there is a risk of accidents such as occurred in the past when color vision standards had not been introduced, because the color vision defect is unchanged. In this context, the history of color vision standards and the color confusion by color defective persons in their daily life were reviewed. The collected data together with pathophysiological characteristics of defective color vision suggest that at least the following measures are necessary from a practical point of view: (1) By education and awareness, color defective persons can avoid errors in color in most cases. Therefore, ophthalmologists should inform them of their defects in childhood and give instructions on how to compensate for their disadvantages. (2) In public and occupational situations, all the information conveyed by color should include lettering or other forms of redundancy for the convenience of color defective persons.

Miscellaneous color vision tests were performed on 66 eyes in 46 acquired blue-yellow deficiency cases, in which the deficiency resembled congenital tritanopia. The confusion loci converged at a point on the short wavelength side of the spectrum in central chorioretinopathy, diabetic retinopathy, branch retinal vein occlusion, retinal pigmentary degeneration, and macular degeneration. However, the confusion loci of glaucoma differed from those of the other 5 diseases of the retina. They crossed the purple boundary, showing a unique tendency among the diseases exhibiting acquired blue-yellow deficiency. In these diseases, except in chorioretinopathy, no correlation was observed between visual acuity, visual field and color confusion.

Monochromatic ERG b-waves were recorded in normal eyes, cataractous eyes and pseudophakic eyes implanted with non-UV or UV IOLs. ERG b-waves were elicited by fourteen monochromatic stimulus lights ranging from 400 to 660 nm under white light adaptation, and spectral response curves were obtained from b-wave amplitudes. Compared with normal eyes or cataractous eyes, the relative b-wave amplitude of pseudophakic eyes was significantly larger in the short wavelength range from blue to green. Except for 400 nm, the spectral response curve of the eyes implanted with UV IOLs was similar to that of eyes implanted with non-UV IOLs. These results suggested that dyschromatopsia might not only occur in eyes implanted with non-UV IOLs but in eyes with UV IOLs.

Confusion lines, convergence points, and neutral points in dichromatism were examined using various surface colors. Confusion lines were obtained from 8 cases of protanopia and 24 cases of deuteranopia by color matching with the surface colors of the Farnsworth-Munsell 100 hue test, then regression analysis was carried out on the cross-points of all confusion lines obtained. Convergence points were obtained and neutral points were also calculated. The convergence point obtained from protanopia using surface colors converged to x = 0.811 and y = 0.189, which is a point near Pitt and Judd's convergence point. The confusion line gradient obtained from deuteranopia was steeper than that of Pitt and Judd's line. The convergence point of deuteranopia was x = 1.959 and y = -0.959. Compared with previous reports, it was in the lower right region. The neutral point of protanopia was in the vicinity of 495 nm and that of deuteranopia in the vicinity of 500 nm. These two values were almost the same as the values in Judd's report. Considering the results mentioned above, the neutral point obtained with surface colors was almost the same as that obtained with spectrum color. From the above results, the convergence point was thought to be different from that obtained using spectrum color. In particular, the difference was significant in deuteranopia.

The diagnosis of blue cone monochromatism (BCM) is based on severely affected color vision with preserved blue function, nearly absent photopic ERG, and a family pedigree compatible with X-linked inheritance. In the past, there has been no familial report of BCM in Japan. We found a Japanese family with BCM and studied the ocular findings of three affected members and a female carrier. Two of three affected members showed unique properties of BCM in their visual functions, including color vision and ERG. One affected member, a brother of their mother (43 years old), showed achromatic color vision. He had diabetic retinopathy and moderate cataract, which, might have disturbed his preserved blue cone function, resulting in the achromatic vision. A female carrier showed normal visual function, except that her photopic ERG was slightly reduced in amplitude.

The gene structures of three color pigments have been reported by Nathans et al. in 1985. One copy of red gene and 1 to 3 copies of green genes are tandemly repeated on X chromosome. As the structures of red and green genes are highly homologous (96%) and tandemly repeated, they cross-over on chromosome during meiosis and hybrid genes were produced. The function of these hybrid genes exhibits abnormal spectrum for red and green light. The 5' portion of the gene determines which cone cell type express the gene and the 3' portion of the gene determines the type of spectrum. In the 3' portion, exon 4 are associated with a small shift of spectrum and exon 5 determines a large shift of spectrum. For example, a hybrid gene with 5' region of red and 3' region of green is expressed in the red cones and exhibits green spectrum. Abnormality of color perception depends on the hybrid ratio of red and green genes.

Patients with macular diseases such as x-linked juvenile retinoschisis, cone dystrophy, and age-related macular degeneration were studied regarding color vision defects. In 9 of 15 eyes of patients with x-linked juvenile retinoschisis, blue-yellow defects were demonstrated. In the older patients with this dystrophy, color vision defects were more severe than in younger ones. Fluorescein angiography revealed retinal pigment epithelium (RPE) atrophy at the macular area in these older patients. Therefore, it was suggested that the color vision defects were due to dysfunction of the outer sensory retina, occurring secondarily to the inner sensory retina. In patients with cone dystrophy, all the examined eyes showed severe color vision defects. It was proved that the size of the atrophic lesion which when ophthalmoscopically evaluated was found to have some relationship with the degree of color vision defects. In patients with age-related macular degeneration, most of the examined eyes showed color vision defects. Moreover eyes with soft drusen formation and/or RPE detachment usually showed more severe color vision defects than the eyes with hard drusen formation and/or RPE atrophy.

In order to study the deuteranopic convergence points we compared the patterns of the simulated panel D-15 test with the actual data from 73 cases of deuteranopia. It was found that 39 of the 73 cases matched one of the four simulation patterns perfectly while another 25 cases showed similar patterns. Of the 64 cases, 9 cases matched the simulated pattern obtained when the x chromaticity coordinates were between 1.1810 and 1.4319, 42 cases when they were between 1.4320 and 2.2588, 7 cases when they were between 2.2589 and 3.6255 and 6 cases when they were between 3.6256 and 4.6572. These results confirm that there are significant individual differences in the convergence points of deuteranopes and support the theory that the confusion lines meet at a specific point rather than running parallel.

In order to determine whether or not the patterns of the panel D-15 test for congenital red-green dichromats change when the convergence point is changed, a simulation experiment was attempted assuming that dichromats arrange the color caps in the order of the slope of the line between the chromaticity coordinates of the color cap and the convergence point. For this procedure, chromaticity coordinates of the color cap were calculated using both the spectral distribution of standard illuminant C and the daylight fluorescent lamp (Toshiba-EDL). For this prediction, the chromaticity coordinates of the convergence points were changed according to y = 1-x. The results show several different patterns for both protanopia and deuteranopia under both illuminants. The range of the x chromaticity coordinates common to both illuminants was 0.6868 to 0.8552 when the protanopic patterns were obtained, while the range of the x chromaticity coordinates common to both illuminants for deuteranopic patterns was 1.0878 to infinity and minus infinity to -1.8153. As a result, it was suggested that the patterns of the panel D-15 test for red-green dichromats change according to the convergence points. Therefore, it was considered that this test cannot be used as a dependable measurement for color discrimination ability in cases showing dichromatic patterns.

In order to study the theoretical patterns of the panel D-15 test for congenital dichromatic color vision defects, the spectral reflectance for the 16 color caps of the panel D-15 test was measured with a spectro-photometer. Then, the chromaticity-coordinates of each color cap were calculated using the spectral distribution of standard illuminant C. The theoretical patterns of the panel D-15 test for dichromats were obtained based on the confusion lines. For this procedure, the slope of the line between the color cap and the convergence point on the CIE chromaticity diagram was obtained first. Then, the order of the arrangement was decided starting with the slope having the smallest cap number and continuing progressively. For the chromaticity coordinates of the convergence points the following values were used; x = 0.7465, y = 0.2535 for protanopia, x = 1.08, y = -0.08, x = 1.40, y = -0.40, and x = 1.70, y = -0.70 for deuteranopia, and x = 0.171, y = 0.000 for tritanopia. The results show a very clear similarity between the orientation axis obtained by simulation and the actual data. Therefore, it was confirmed that dichromats arrange the color caps in the order of the slope of the line between the color cap and the convergence point, when performing the panel D-15 test. Furthermore, it was suggested that the patterns of the panel D-15 test differ by the convergence points among dichromats even of the same type.

Using an Equi-Energy-Color Pattern Generator, color vision experiments were performed on nine normal subjects, six cases of deuteranomalies, and six cases of deuteranopias with the use of Visually-evoked cortical potentials (VECPs). Checkerboard patterns, consisting of the pairing of any chosen one of three colors with its complementary color in terms of equal energy, were used. The pairing of a neutral color with its complementary color of protan, deutan and tritan were displayed on a color TV monitor. We measured the amplitude and latency of P100 component of VECPs. Cases of deuteranopia showed significantly smaller amplitude and longer latency of P100 component in protan and deutan responses than did normal subjects. Cases of deuteramomaly showed significantly smaller amplitude and longer latency of P100 component in only protan response compared to those of normal subjects. It was possible to objectively detect the deutan in color pattern VECPs.