Prototyp eines Bildschirmfarbtests

2021 ◽  
Vol 1 (5) ◽  
pp. 172-177
Author(s):  
Wolfgang Cagnolati
Keyword(s):  
Colour Vision ◽  
Test Material ◽  
Colour Perception ◽  
Vision Disorder ◽  
Digital Testing ◽  
Colour Scale ◽  
Colour Sense ◽  
Normal Colour ◽  
The Difference ◽  
Vision Defects

Purpose. The purpose of this study is to develop a new digital colour vision test. Material and Methods. Based on the principle of metamerism, a digital testing strategy was developed for efficient measurement of colour vision. Twentyfive subjects participated in the study, 21 of whom had normal colour vision and four of whom had a congenital colour vision disorder. Differences in colour vision were examined by monocular presentation of halfquadrants of different hues and degrees of saturation, and the algorithm calculated the colour vision defects that occurred based on the subjects’ responses. The following colour vision values were assigned from the data: a colour scale range of 2.76 – 7.18 for normal colour vision and greater than 7.18 for colour sense disorders. A second new colour scale assessed the type of colour vision disturbance: in the range of 0 – 0.3 were values for a deuteranomaly, in the range of 0.6 – 1.0 were values for a protanomaly, and a value of 1.0 corresponded to a tritanomaly. Results. The difference in colour vision between subjects with normal colour vision and those with a colour vision defect was confirmed (p < 0.001) by measuring the type and the extent of the colour vision disorder was determined. In the group of subjects with normal colour perception, a mean colour scale value of 3.41 ± 0.52 was determined. The extent of colour sense disturbance for the subjects with colour vision impairment was values of 7.18 – 14.33 according to the colour scale, indicating greater variability. Conclusion. The developed algorithm provided meaningful results regarding the colour perception of the test persons. It was possible to differentiate between normal colour vision and colour vision disorder could be shown. Furthermore, the variation between subjects with normal colour vision could be evaluated. Keywords. Colors, colour vision, colour sense disorders, colour test, software algorithm

scholarly journals Effect of optical defocus on colour perception

2007 ◽  
Vol 66 (2) ◽  
Author(s):  
R. R. Sehlapelo ◽  
A. O. Oduntan
Keyword(s):  
Visual Acuity ◽  
Young Adult ◽  
Colour Vision ◽  
Vision Screening ◽  
Distant Object ◽  
Colour Perception ◽  
Daily Experience ◽  
Optical Correction ◽  
Normal Colour ◽  
Optical Defocus

Daily experience shows that colour  of a very distant object cannot be accurately determined.  It is assumed that visual acuity (VA) loss is one of the factors at play in this case.  The effects of reduced VA as a result of refractive error or optical defocus on colour vision have not been examined.  Such study willdictate the need or otherwise for optical correction before assessment of colour vision.  The purpose of this study therefore, was to investigate the effects of optical defocus on colour vision in individuals with normal colour vision.  Twenty nine young adult subjects (11 male and 18 females) were included in this study. Their ages ranged from 11 to 29 years with a mean of 22.1 ± 3.4 years.  All subjects had VA of 6/6 or better and normal colour vision.  The colour vision was evaluated with the Farnsworth panel D-15 (desaturated). Each subject was optically defocused to VA of 6/24, 6/60 and 1/60(6/360) at 6 meters respectively and colour vision was assessed at each reduced VA.  At VA of 6/24, colour vision was not affected in all subjects. When the VA was reduced to 6/60, however, 15 (51%) of the subjects failed the colour vision test. When the VA was further reduced to 1/60 by optical defocus, 24 (83%) of the subjects failed the colour vision test.  It was concluded that optical defocus and reduced VA can adversely affect colour vision test findings. While VA reduction to 6/24 may not affect the colour vision results, VA of 6/60 can.  It is therefore, recommended that in clinical colour vision  testing and colour vision screening, VA should first be assessed andcompensated, especially if uncorrected VA is 6/24 or worse.  

scholarly journals Chromagen lenses and abnormal colour perception

2011 ◽  
Vol 70 (2) ◽  
Author(s):  
O. Matthew Oriowo ◽  
Abdullah Z Alotaibi
Keyword(s):  
Colour Vision ◽  
Contact Lenses ◽  
Individual Case ◽  
School Age Children ◽  
Colour Perception ◽  
Colour Vision Deficiency ◽  
Different Types ◽  
Wavelength Filter ◽  
Vision Defects ◽  
Case Basis

Background: The Chromagen lens system comprises of tinted spectacle or contact lenses, each with a specific colour wavelength filter which controls the spectra of the light entering the eye. This study investigated whether spectacle-mounted Chromagen lenses would enhance colour perception in individuals with abnormal colour vision.Methods: The Ishihara colour test was used to test for colour vision deficiency (CVD) and also to evaluate the effect of the Chromagen spectacle lens on colour perception in 13 subjects. An Oculus Anomaloscope was used to confirm and sub-classify the types of CVD. Subjects comprised of school age children from the Riyadh area in Saudi Arabia.Results: The distribution amongst the male participants comprised two subjects with protanomaly, two with protanopia, five with deuteranomaly, and two with deuteranopia. Amongst the two female participants, one subject showed deuteranomaly, and one showed protanomaly. Different types of Chromagen spectacle lenses displayed some levels of colour vision enhancement depending on type of CVD.Conclusion: The findings support the notion that chromagen lenses could enhance colour vision perception in some cases of red-green colour vision defects. Clients with CVD should be managed on an individual case basis. (S Afr Optom 2011 70(2) 69-74) 

Frequency of Colour Vision Defects Among Zulus in Natal

1981 ◽  
Vol 13 (2) ◽  
pp. 241-248 ◽  
Author(s):  
R. W. Pickford ◽  
Ruth Pickford
Keyword(s):  
Colour Vision ◽  
The Difference ◽  
Vision Defects ◽  
Black Populations ◽  
Number Of Males

SummaryThe HRR test was used to study the frequency of colour vision defects in 297 Zulu men and 43 Zulu women of Natal, two Basuto men in Natal, and two Swazi men and 21 Swazi women in the Transvaal.The frequencies agree with the work of other authors, that the numbers of red–green defectives in the black populations of Africa are less than half those among European whites. The observed frequency of women defectives is greater than that expected from the number of males, and the difference is probably due largely to the inclusion of a small number of women with considerable heterozygous manifestation.No yellow–blue deficient subjects were found.

scholarly journals An Ishihara-style test of animal colour vision

2018 ◽  
Author(s):  
Karen L. Cheney ◽  
Naomi F. Green ◽  
Alexander P. Vibert ◽  
Misha Vorobyev ◽  
N. Justin Marshall ◽  
...  
Keyword(s):  
Colour Vision ◽  
Weber Fraction ◽  
List Type ◽  
Colour Perception ◽  
Sensory Bias ◽  
Long Wavelength ◽  
Single Target ◽  
Normal Colour ◽  
Behavioural Tests ◽  
Colour Signals

AbstractColour vision mediates ecologically relevant tasks for many animals, such as mate choice, foraging and predator avoidance. However, our understanding of animal colour perception is largely derived from human psychophysics, even though animal visual systems differ from our own. Behavioural tests of non-human animals are required to understand how colour signals are perceived by them.Here we introduce a novel test of colour vision in animals inspired by the Ishihara colour charts, which are widely used to identify human colour deficiencies. These charts consist of dots that vary in colour, brightness and size, and are designed so that a numeral or letter is distinguishable from distractor dots for humans with normal colour vision. In our method, distractor dots have a fixed chromaticity (hue and saturation) but vary in luminance. Animals can be trained to find single target dots that differ from distractor dots in chromaticity. We provide Matlab code for creating these stimuli, which can be modified for use with different animals.We demonstrate the success of this method with triggerfìsh, Rhinecanthus aculeatus, and highlight behavioural parameters that can be measured, including success of finding the target dot, time to detect dot and error rate. Triggerfìsh quickly learnt to select target dots that differed from distractors dots regardless of the particular hue or saturation, and proved to use acute colour vision. We measured discrimination thresholds by testing the detection of target colours that were of increasing colour distances (ΔS) from distractor dots in different directions of colour space. At least for some colours, thresholds indicated better discrimination than expected from the Receptor Noise Limited (RNL) model assuming 5% Weber fraction for the long-wavelength cone.This methodology seems to be highly effective because it resembles natural foraging behavior for the triggerfìsh and may well be adaptable to a range of other animals, including mammals, birds, bees and freshwater fish. Other questions may be addressed using this methodology, including luminance thresholds, sensory bias, effects of sensory noise in detection tasks, colour categorization and saliency.

scholarly journals Inherited colour vision deficiencies: From Dalton to molecular genetics

2005 ◽  
Vol 133 (11-12) ◽  
pp. 521-527
Author(s):  
Dragana Cvetkovic ◽  
Dobrosav Cvetkovic
Keyword(s):  
Molecular Basis ◽  
Colour Vision ◽  
Molecular Genetic ◽  
Regulatory Region ◽  
Cone Opsin ◽  
Opsin Genes ◽  
The Difference ◽  
Vision Defects ◽  
Hybrid Genes ◽  
Cone Opsins

In recent years, great advances have been made in our understanding of the molecular basis of colour vision defects, as well as of the patterns of genetic variation in individuals with normal colour vision. Molecular genetic analyses have explained the diversity of types and degrees of severity in colour vision anomalies, their frequencies, pronounced individual variations in test results, etc. New techniques have even enabled the determination of John Dalton?s real colour vision defect, 150 years after his death. Inherited colour vision deficiencies most often result from the mutations of genes that encode cone opsins. Cone opsin genes are linked to chromosomes 7 (the S or ?blue? gene) and X (the L or ?red? gene and the M or ?green? gene). The L and M genes are located on the q arm of the X chromosome in a head-to-tail array, composed of 2 to 6 (typically 3) genes - a single L is followed by one or more M genes. Only the first two genes of the array are expressed and contribute to the colour vision phenotype. The high degree of homology (96%) between the L and M genes predisposes them to unequal recombination, leading to gene deletion or the formation of hybrid genes (comprising portions of both the L and M genes), explaining the majority of the common red-green colour vision deficiencies. The severity of any deficiency is influenced by the difference in spectral sensitivity between the opsins encoded by the first two genes of the array. A rare defect, S monochromacy, is caused either by the deletion of the regulatory region of the array or by mutations that inactivate the L and M genes. Most recent research concerns the molecular basis of complete achromatopsia, a rare disorder that involves the complete loss of all cone function. This is not caused by mutations in opsin genes, but in other genes that encode cone-specific proteins, e.g. channel proteins and transducin.

scholarly journals Comparative Analysis of Methods and Tests for Testing Colour Vision of Professional Seafarers

2012 ◽  
Vol 1 (2) ◽  
pp. 69-76
Author(s):  
Veljko Rogošić ◽  
Lovro Bojić ◽  
Nikola Kolja Poljak ◽  
Darko Duplančić ◽  
Pero Vidan ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Colour Vision ◽  
Road Traffic ◽  
Correct Choice ◽  
Diagnostic Methods ◽  
Correct Interpretation ◽  
Vision Disorder ◽  
The Difference ◽  
Maritime Air ◽  
Interpretation Of Results

There are differences among official standards of testing colour vision among different countries, conditioned by out-of date, but still enforceable laws and codes. These standards refer to professions in the maritime, air, rail and road traffic. The criteria for testing colour vision are significantly more severe for professionals involved in traffic. For complex diagnostics of colour vision disorder (dyschromatopsia) there are a number of well-known diagnostic methods and tests (of different cost, validity and year of production) at disposal. The difference of diagnostic methods and tests improves the detection of dyschromatopsia. The requirement is the correct choice of tests, correct mode and correct interpretation of results gained for each individual dyschromatopsia, i.e. profession.

VII.—A New Method of investigating Colour Blindness, with a Description of Twenty-three Cases

1923 ◽  
Vol 42 ◽  
pp. 75-88 ◽  
Author(s):  
R. A. Houstoum
Keyword(s):  
Colour Vision ◽  
Extreme Case ◽  
Original Method ◽  
Colour Perception ◽  
Homogeneous Population ◽  
Normal Colour ◽  
The Subject ◽  
Colour Blindness ◽  
Trained Observers ◽  
The University

During the past four years I have been conducting surveys of the colour vision of students in the University of Glasgow. The first survey was made by a colour-perception spectrometer very similar to Dr Edridge-Green's instrument, and embraced 79 observers. The second survey was made by Dr Edridge-Green's bead test, and embraced 100 observers. The third survey, carried out in collaboration with Miss Margaret A. Dunlop, was made by an original method, called here for short the microscope test, and embraced 1000 observers. At present there are two other surveys under progress. The object of these surveys is to find a numerical method of specifying goodness of colour vision; to see, by the application of statistical methods, whether the colour blind fall naturally into groups or are merely outliers of a homogeneous population; to find whether colour blindness is a Mendelian characteristic for men and merely an extreme case of normal variation for women; and to throw light on the subject of colour vision generally. Consequently, the normal have been investigated with as much care as the colour blind. But in the course of the four years I have made the acquaintance of many trained observers with abnormal colour vision, and have been possessed with an ever-growing desire to know exactly, irrespective of all theory, what was the matter with their colour vision. In spite of the vast literature on the subject, the tests generally have been of a very superficial nature, and unsatisfactory to the man with mathematical instincts. As these abnormal cases were beginning to leave the University, I addressed myself last spring to the problem of finding a method of testing which would describe their condition independent of theory, and, indeed, independent of words. This paper describes how the problem was solved, and gives data for twenty-three cases of colour blindness, four of normal colour vision, and one case of exceptionally good colour vision.

Modelling the effects of inter-observer variation on colour rendition

2017 ◽  
Vol 51 (1) ◽  
pp. 37-54 ◽  
Author(s):  
MJ Murdoch ◽  
MD Fairchild
Keyword(s):  
Colour Vision ◽  
Spectral Characteristics ◽  
Observer Variation ◽  
Light Sources ◽  
Standard Observer ◽  
Natural Range ◽  
Normal Colour ◽  
Range Of Variation

The colour rendition characteristics of light sources are quantified with measures based on CIE standard observers, which are reasonable representations of population averages. However, even among people with normal colour vision, the natural range of variation in colour sensitivity means any individual may see something different than the standard observer. Modelling results quantify the effects of these inter-observer differences on colour rendition measures defined by IES TM-30-15. In general, inter-observer differences tend to be smaller for light sources with high colour fidelity values, and they are affected by spectral characteristics of different lighting technologies. The magnitude of variation in colour rendition measures, up to 5–10 units in IES TM-30-15 ( Rf, Rg), measures is compared with other sources of variability and ambiguity.

scholarly journals How colour palettes in maps are re-coloured by daltonization methods

2019 ◽  
Vol 1 ◽  
pp. 1-2
Author(s):  
Anne Kristin Kvitle
Keyword(s):  
Colour Vision ◽  
Information Graphics ◽  
Male Population ◽  
Colour Perception ◽  
Female Population ◽  
Other Information ◽  
Map Design ◽  
Enhancement Method ◽  
Choropleth Map ◽  
Future Work

<p><strong>Abstract.</strong> The ability of identifying objects and elements based on colour is important in order to decode the information in a map or other information graphics. For this reason, the colours need to appear correct and be perceived in the desired and intended way. Map reading is reported as a challenging task for people with impaired colour vision. In reviews of the challenges of colour vision deficiencies (CVD) in everyday life (Cole, 2004), up to 60 % of the subjects in the studies reported problems in reading colour coded charts, slides and prints. Other studies (Carter and Silverstein, 2010) describes the difficulties to distinguish and identify coloured objects in weather, financial and other maps and charts.</p><p>Colour vision deficiencies are common, where congenital CVD affects about 8 % of the male population and 0.4 % of the female population. In addition, colour vision and colour perception may be affected by medical conditions or injury (acquired CVD) and situational conditions (situation induced CVD).</p><p>Reviews of visual usability and accessible map design conclude that few maps appear to have been designed with CVD users in mind (Cartwright, 2015) and that the design efforts or research of accessible colours palettes for CVD observers are mostly limited to thematic maps such as choropleths (Kvitle, 2018).</p><p>Daltonization methods are image processing methods to automatically enhance information in existing images. A common enhancement method is re-colouring, changing the colours in the original image to make be more distinguishable to the CVD observers. The daltonization method targets a specific type of CVD, and may also have been designed for specific applications (natural images, scientific images, information graphics etc). Therefore, the evaluation of the methods is often based on a limited set of test images. Using one specific map image as input will give very different results based on the daltonization methods.</p><p>The aim of the work is primarily to examine how the colour palettes in a map are altered by different daltonization methods. Second, the aim is to explore how different map types are influenced by the daltonization methods and to propose requirements and guidelines for test images for future work.</p><p> The set of test images in this work includes</p><ul><li>Information graphics (such as a tube map).</li><li>Choropleth map.</li><li>Reference map based on different map providers.</li></ul><p> To illustrate the visual differences, CVD simulation methods are applied on the original images and the daltonized versions of the images.</p>

A Hospital-Based Cross-Sectional Study to Estimate the Prevalence and Sex Distribution of Colour Vision Deficiency among School Going Children Attending a Tertiary Eye Care Center in Kolkata City, West Bengal, India

2021 ◽  
Vol 8 (32) ◽  
pp. 2962-2967
Author(s):  
Rinki Saha ◽  
Indrajit Sarkar ◽  
Tamojit Chatterjee ◽  
Sandip Samaddar ◽  
Suman Chandra Sen
Keyword(s):  
School Children ◽  
Colour Vision ◽  
Care Center ◽  
Cross Sectional Study ◽  
Sex Distribution ◽  
Cross Sectional ◽  
Colour Vision Deficiency ◽  
Cone Pigments ◽  
Normal Colour ◽  
Colour Blindness

BACKGROUND Colour vision is a function of three types of cone pigments present in the retina. Colour vision deficiency is an important disorder of vision that may pose a handicap to the performance of an affected individual. The prevalence of colour blindness varies in different geographical areas. The identification and estimation of the prevalence of colour vision deficiency in school-going children will help to educate and guide the caregivers to help the children in selecting their profession. This study was done to estimate the prevalence, sex distribution, and types of colour vision deficiency among school-going children of 5 to 15 years. METHODS A cross-sectional observational study was done among 500 students to evaluate the colour vision during the period from 1st January 2018 to 30th June 2019 at the Regional Institute of Ophthalmology, Kolkata. Ishihara’s pseudo isochromatic colour vision chart 38th edition was used to assess the school children for colour vision status. The children who were found to be colour blind were further classified into degree and types of colour vision deficiency. RESULTS A total of 500 students (250 male & 250 female) of surrounding schools, in the age group of 5 years to 15 years, were screened. 480 students (96 %) had normal colour vision while 20 (4 %) students were found to have defective colour vision. Prevalence (4 %) for colour blindness was found to be higher in males (3.6 %) than females (0.4 %). It was observed that out of 20 (4 %) colour-blind subjects 3.6 % were protanopes and 0.4 % were deuteranopes. CONCLUSIONS The present study shows the prevalence of colour blindness found to be quite low (4 %) and more common in males (3.6 %) in comparison to females (0.4 %). Protanomaly (3.6 %) was more common than deuteranomaly (0.4 %). KEYWORDS Colour Blindness, Protanomaly, Deuteranomaly, School Children

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