Red-green Defects Research Articles

Tokyo Medical College Test in acquired dyschromatopsia.

In order to find a successor for the Hardy, Rand and Rittler (AOH-R-R) test the author made a comparison between the AOH-R-R and the Tokyo Medical College (TMC) tests in acquired dyschromatopsia. The diagnosis of the TMC type of a red-green defect is often in contradiction with the results of other color vision tests. In grading the severity of a red-green defect the TMC classification is shifted with regard to the AOH-R-R classification. A corrected grading in better agreement with the AOH-R-R classification is proposed. The TMC blue-yellow screening plates are more sensitive than the AOH-R-R blue-yellow screening plates. A TMC (supermild) blue-yellow defect in general corresponds to blue-yellow defects detected by FM 100 Hue and its derivatives. In the study of acquired dyschromatopsia, it is necessary to use a test battery. In our opinion the TMC can be used in such a test battery although it is not a real successor to the AOH-R-R. If ever the AOH-R-R is reprinted, the blue-yellow plates should be extended to a 'supermild' degree as are the TMC blue-yellow plates.

SCREENING OF RED‐GREEN DEFECTS OF COLOUR VISION WITH PSEUDOISOCHROMATIC TESTS

Fifty red-green defectives and 100 normal subjects were examined with the second edition of the Boström-Kugelberg (BK II, 1972) series and the Ishihara complete edition (1976) of pseudoisochromatic plates. The results are related to those obtained with the first edition of the Boström-Kugelberg test (BK I, 1944) and the Boström test (II B, 1950) and to the classification of defects obtained with the Nagel anomaloscope. The 50 red-green defectives were originally selected by using a combination of the BK I and II B tests. The normal subjects also, passed this preliminary test, as well as an examination with the Nagel anomaloscope. In the final examinations performed under standardized conditions, three red-green defectives passed both the BK II and the BK I test, while eight defectives passed the Ishihara test. Combination of BK II or BK I test with the Ishihara test does not improve the result. Only one defective (a borderline case of protanomaly) passed the separate II B test. Normal subjects were not classified as colour defectives with any of the four pseudoisochromatic tests used. All normal subjects passed both the BK II and the Ishihara test. Classified as suspected red-green defectives (one misreading made in standardized conditions) were five normal subjects with the II B test and one normal subject with the BK I test. In the second edition of Boström-Kugelberg series, the plates numbered 3, 5, 11, 16 and 18 are clearly less effective than respective plates of the first edition. Only the plates numbered 1 and 10 have markedly improved in the second edition. Red-green defectives made on average 0.54 misreadings per plate in the BK II test as compared with respective 0.62 in BK I, 0.69 in the Ishihara and 0.56 in the II B test.

Dominant Cystoid Macular Dystrophy

Of 24 examined family members, 14 had an undescribed macular dystrophy. There is a clear autosomal-dominant heredity. Essential features of the disease are pigmentary disturbance, cystoid macular edema, wrinkling of the internal limiting membrane, and vitreous body changes. In this family there was an increased incidence of severe hyperopia (greater than or equal to 6 diopters). As the disease progressed color vision deteriorated (type 1 acquired red-green defect), disturbance of the electro-oculogram became more prevalent, and the electroretinogram was normal. These finding differentiate this dystrophy from other diseases with a bull's eye aspect or cystoid macular edema and from vitreoretinal syndromes.

Retinal functions in dominant cystoid macular dystrophy (DCMD).

Dominant cystoid macular dystrophy (DCMD) occurred in 28 members of 5 unrelated families. The disease is characterized by cystoid macular oedema and leakage from retinal capillaries in the posterior pole. Colour vision examination reveals a type I red-green defect with concomitant blue-yellow defectiveness; the latter may be caused by the leaking capillaries. The ERG is normal. The EOG is subnormal. Darkadaptation curves are often slightly disturbed. There are frequently also aspecific pigmentary alterations in the peripheral fundus.

Anomaloscopic Survey of Blue-Yellow Defects Among School Children in Santiago

A survey of color vision defects was performed on a random sample of 138 Santiago male school children aged 14-15 years. Over-all incidence of red-green defects was found to be 4.34 percent. Blue-yellow minor defects were found in 17 cases (12 percent). The following major defects were found: extreme tritanomaly plus extreme tetartanomaly (1 case), and extreme tetartanomaly plus weak tritan defects (2 cases).These results suggest a probable incidence of 2.16 percent of congenital blue blindness in the general male population of Santiago, Chile.

Metameric ‘Color Rule’ matches of normal, colour deficient, cataractic, and aphakic observers

SUMMARYMetameric matches on the ‘color rule’ under various kinds of illumination, principally of colour temperature 6500°K and 2400°k, were established for colour normal people of both sexes, various ages and ethnic origin. The matches shift in a way which is explicable by the yellow discoloration of the lens and possibly other optic media, with age and general pigmentation.Individuals defective in colour perception differ ‐ as a group ‐ from normal people not only in the position of the average match co‐ordinates, but mostly also in a wider tolerance of accepted matches. By combining average match with tolerance area a useful criterion can be shown to exist for discriminating between normal, protanomalous and deuteranomalous people and to a lesser extent between the two principal classes of dichromats. Similar distinctions can be derived by inspecting the orientation and position of tolerance areas, which for red‐green defects are diagonally oriented but in one tritan defective appeared horizontal.The versatility, cheapness and convenience of the ‘color rule’ for colour vision studies in the field is pointed out.

Liebreich's sign for defective colour vision among artists.

LIEBREICH1 pointed out that in a London exhibition of 1871 a painting showed roofs an oxen red on the sunny side but green where shadowed. He suggested that it indicated that the painter was a red–green colour vision defective. Angelucci2 called this “Liebreich's sign” when he described the works of six painters known to be red–green defectives, whose pictures showed this characteristic. Trevor-Roper3 and Kalmus4 also mention Liebreich's sign.

COLOR-VISION DEFECTS IN AMERICAN SCHOOL CHILDREN.

A study of color-vision using Ishihara plates and the pseudoisochromatic plates designed by Hardy, Rand, and Rittler (HRR) was made of 10,341 students in all grades in an American school district. The tests were compared and the Ishihara plates were found more accurate for detecting defects, and the HRR more apt to give problems in interpreting results for borderline situations. The HRR was found more useful in classifying the type of red-green color-vision defect present in severely affected cases and for detection of defects in perception involving blues and yellows. Among the 5,263 boys, 6.2% had a defect, and 0.55% of the 5,078 girls had a defect. An unexpected ancillary finding was the lack of student, parental, and teacher recognition of the presence of color-perception problems in a majority of those identified.

A Pedigree for Three Types of Colour-Vision Defect

THE following pedigree is of interest because it shows three types of red-green colour vision defect together, namely, protanopia (P), extreme protanomaly (EPA) and protanomaly (PA) with darkened red, and because it supports the theory that PA is dominant to EPA1,2.

Red anomaly dominant to protanopia.

RED anomalous colour vision is the rarest type of sex-linked red-green colour vision defect1,2, and I have found it only twelve times among 173 men and twice among 23 women who were red-green major defectives. It takes two forms, one with, and the other without, the darkened red of the protanope. These are found in about equal proportions.

Brightness and Saturation of Colours in Red-Green Defectives

FOR theories of colour vision it is important to consider the relationships between the saturation and photopic brightness-levels of certain colours for anomalous and red-green blind subjects.

Colour Vision of Heterozygotes for Sex-linked Red-Green Defects

SEX-LINKED red-green colour vision defects are incompletely recessive, since the heterozygotes for these defects and the normal condition usually have small red-green defects1–3, or may occasionally manifest the major defects themselves4. Details of the relationships between the different defective allelomorphs5 and the small defects of these heterozygotes have not been fully revealed ; but the appended table shows the most marked characteristics of the red-green vision of seventy-three women (not major defectives) who have relatives with major defects, classified according to the defects of those relatives.

Frequencies of Sex-Linked Red-Green Colour Vision Defects

In a research carried out during the last five years on subjects in the west of Scotland, with an apparatus which efficiently discriminates between major (sex-linked) red-green defectives and ordinary colour-weak individuals, 7.8 per cent of male and 0.65 per cent of female sex-linked defectives were found in 464 males and 460 females. This corresponds well with the results of researches in which the Ishihara Test was used1,2,3. The expected frequency of female defectives would be 0.61 per cent, with 7.8 per cent of males in the population. The observed frequency of 0.65 per cent is not statistically different from this figure, and it suggests that there is little truth in the common belief that there are more colour-blind women in the population than would be expected. The extra ones are heterozygotes, some of whom are doubtful passes on the Ishihara test.

Pseudo-lsochromatic Plates for Testing Color Perception

This consists of a paneled folder containing forty-six charts of the general type devised by Ishihara but presenting many improvements, evident only after a comparative test on the same subjects. The panels are not numbered and are so arranged that any desired pair may be exhibited alone and in any order. These provisions will facilitate the detection of malingerers. Inserted in a pocket in the folder, which is of substantial construction, is a pamphlet giving a brief discussion of color blindness, description of types, and instructions for making the tests and interpreting the results. There is also a brief bibliography and a tabular key for interpreting each plate. Most of the plates are applicable only to red-green defects, but there are several especially designed for the detection of blue-yellow defects. On the whole the equipment makes possible a some-what more comprehensive examination but the technic is greatly simplified as compared