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PubMedDate not supplied

[The examination of color vision using a 2 metameric equation method].

Modern anomaloscopes with four independent light channels (i.e. Besançon-Anomalometer which was presented in 1979 at the SFO Congress) allow accurate examinations of color vision. In our routine clinical examination, we use two metameric equations: the red-green Rayleigh equation and the blue-green Moreland equation. This so called Two-Equation-Method enables the diagnosis of congenital and acquired color vision defects in a precise qualitative as well as quantitative way. For both equations the goal of the examination is to measure the absolute matching range. Abnormal color vision is diagnosed if the absolute matching range is shifted and/or enlarged in one or both of the two metameric equations. In congenital colour vision deficiencies, the results are similar to those obtained with the Nagel anomaloscop. The different types of acquired defects are compared with the types of Verriest's classification. A computer controlled clinical examination of color vision, which will make the procedure simplier and shorter for the patient is actually being developed.

Color Perception↗
PubMed1989

[Theoretical patterns of the panel D-15 test in congenital dichromatic color vision defects].

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.

Color Perception↗
PubMed1989

[Theoretical patterns of the panel D-15 test in congenital red-green dichromats as a function of the chromaticity coordinate of the convergence points].

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.

Color Perception↗
PubMed1977

[A new sieve-test for testing colour vision (author's transl)].

From our results we can be sure that the colour test disk is at least as reliable for mass testing for colour blindness as the Ishihara isochromatic colour plates. In practice the test disk has the advantage of constancy of testing conditions and easy and quick procedure. If it is necessary to differentiate between protopia and deuteropia the colour test disk is significantly better Ishihara's colour plates.

Color Perception↗
PubMed1978

Further observations on the extramacular chromatic mechanisms.

Monochromatic targets presented at 30 degrees excentricity on orange, magenta and blue backgrouds are used. A small monochromatic light, 476 nm on orange, 551 nm on magenta and 621 nm on blue, is flashed at 3 cps-1 on the centre of the targets. The size of the targets is varied and their luminance adjusted using neutral filters until the flashing light is just not visible. This method allows the study of chromatic mechanism sensitivity and of retinal interactions (summation and inhibition). Some observations in normal as well as in pathological conditions are presented.

Adult↗
PubMed1977

The Mackenzie Memorial Lecture, 1977. Of divers colours.

I shall discuss the nature of the sensation of colour and the reason for our colour vision, leading on to the existence of defects in that sense. I will consider the different kinds of such defects and the arguments for the use of particular tests in varying circumstances. I report the result of a recent survey of the value of a careers advisory service for "colour blind" school children seen between 1965 and 1977 (primarily red-green blind). This leads to examples of the value of these tests in genetics, and in the early diagnosis of disease or toxicity. I shall also describe the various modifications I have made to the 100-hue test, with its eventual automation both for computation and recording. Finally, the recommendations I make for future progress cover routine examination, both on starting primary education and on entering secondary education, analysis of the colour task at work, and the adoption of an enlightened system of colour coding.

Adolescent↗
PubMed1979

Clinical implications of color vision research.

The attributes of color and the mechanisms underlying normal and defective color vision are reviewed. The clinical implications of some research efforts bearing on congenital and acquired color defects, peripheral color vision, and the influence of photostable pigments on color vision and color vision tests is presented. This presentation is intended to illustrate how selected avenues of research have contributed to our understanding of color vision and to demonstrate the clinical utility of that research.

Color Perception↗
PubMed1979

Colour vision tests and colour naming by thirteen incomplete achromats in Bishnupur.

As an exploratory study six colour vision tests were given to nine male and two female achromats from the Shankhabanik community in Bishnupur, and to two additional similar males. All thirteen subjects had severe photophobia, fixation nystagmus, extreme weakness of vision (4/24 to 3/60) and the red end of the spectrum was much shortened. This research indicates that they had a form of incomplete achromatopsia, varying from an almost complete to a very severe partial loss of colour vision. The condition is inherited as an autosomal recessive. The most likely interpretation of these cases is that they are incomplete rod achromats. Their performance on the colour vision tests is tabulated, and shows complete inability to do the Ishihara test; nearly complete inability on the HRR test, with a possible slight tendency to do better in the yellow-blue than the red-green sub-tests; on Sloan's test they show approximate accordance with her results for achromats; they have severe difficulty with the dichotomous and 100-hue tests, with a possible slight tendency to make fewer errors on the G/B sections. The anomaloscope shows little abnormality of mid-matching points, but great increases in average matching ranges above the normal, although not absolute loss of colour sense, but with extreme darkening or shortening of the red end of the spectrum. Their colour naming was carefully recorded, and was fairly good occasionally, sometimes erroneous without being wildly at fault, and most often completely wrong. The records of colour naming were made, not, of course, as a form of colour vision test, but simply to illustrate the ways in which such defectives make an effort to use colour names in general use among their friends and relatives.

Adult↗
PubMed1987

[Color vision].

Explore the source record for details and available documents.

Color Perception↗
PubMed1986

Spectral sensitivity for observers with protanomalous, extreme protanomalous and protanopic colour vision.

Contemporary models of colour vision include a channel for luminosity arising from a combination of some or all of the cone outputs. Accordingly any alteration, reduction or loss at the cone level ought to affect the shape of the spectral sensitivity curve, yet there have been few reports of any significant differences being found between the curves of protanomalous and protanopic subjects. A modified minimum flicker technique was used to determine the spectral sensitivity curves of observers with protanomalous, extreme protanomalous and protanopic vision. Significant differences were found among the mean curves of these categories of vision from 550 nm upwards.

Adolescent↗