scholarly journals Color-Vision Mechanisms in the Peripheral Retinas of Normal and Dichromatic Observers

1973 ◽  
Vol 61 (2) ◽  
pp. 125-145 ◽  
Author(s):  
B. R. Wooten ◽  
George Wald
Keyword(s):  
Color Vision ◽  
Color Blindness ◽  
Neural Pathways ◽  
Color Adaptation ◽  
Normal Retina ◽  
Fixation Area

It is possible that so-called normal trichromatic vision occurs only between the central blue-blind fixation area and about 30° peripherally. Beyond about 30° vision has been alleged to become dichromatic (red-green blind), and beyond about 60°, monochromatic. Hence every form of color blindness may characterize various zones of the normal retina. We have studied mechanisms of peripheral color vision, mainly by measuring the spectral sensitivities of the blue-, green-, and red-sensitive systems, isolated by differential color adaptation. In normal observers the sensitivity of the blue-mechanism falls off about 2 log units by 80° out. The green- and red-sensitive systems decline only about 0.7 log unit over the same range. Protanopes, deuteranopes, and tritanopes exhibit comparable changes. We have not found any color mechanism present centrally to be wholly lost peripherally. Nor, for dichromats, have we found any mechanism missing centrally to be present peripherally. Whatever evidences of peripheral color blindness have been observed appear to involve other mechanisms than failure of receptors, probably including some fusion of neural pathways from receptors to centers.

Color-blindness simulation for red-green and blue-yellow ambiguity

2021 ◽  
pp. 1-12
Author(s):  
Sheida Anbari ◽  
Hamid Reza Hamidi ◽  
Shokoh Kermanshahani
Keyword(s):  
Color Vision ◽  
Color Perception ◽  
Color Blindness ◽  
Daily Activities ◽  
Reasonable Accuracy ◽  
Simulation Performance ◽  
Normal Color Vision ◽  
Test Kit ◽  
Different Types ◽  
Color Vision Test

Color blindness has important effects on people’s daily activities, since most activities require a discernment between colors. It is very important for engineers and designers to understand how colorblind people perceive colors. Therefore, many methods have been proposed to simulate color perception of people affected by Dichromacy and anomalous Trichromacy. However, the simulation results rarely have been evaluated with the reports of concerned individuals. In first study, we tried to simulate the color perception of people with different types (red and green) and different degrees of color blindness. Different degrees of red-green deficiency is simulated on the 24-plates brand of the Ishihara color vision test kit. Then simulated plates were tested on people with normal color vision. The results show that the simulation performance is better in the case of high degrees of red-green deficiency. There is also a clear difference between the assessment of female and male volunteers. In another study, the perception of the color of people with blue-yellow blindness is also considered. The proposed blue-yellow blind simulation is compared with the result of another research project. The results show that the color perception of individuals with different degrees of blue-yellow blindness can be reconstructed with a reasonable accuracy.

Color Blindness in Mentally Retarded Children

1969 ◽  
Vol 35 (8) ◽  
pp. 609-616 ◽  
Author(s):  
Jerome D. Schein ◽  
John A. Salvia
Keyword(s):  
Sex Differences ◽  
General Population ◽  
Color Vision ◽  
Mentally Retarded ◽  
Color Blindness ◽  
Instructional Materials ◽  
Normal Children ◽  
Color Blind ◽  
Mentally Retarded Children

Recent studies of mentally retarded children have found substantially higher rates of color blindness than are usually reported for the general population. In 2 of these studies, sex differences in color blindness, invariably found in intellectually normal children, do not appear. Reanalysis of data from one of the studies of retarded children suggests the possibility that the high rates arise from the difficulty in comprehending the test and following the directions rather than from faulty color vision. However, even if the number of color blind retarded children is actually lower than these studies show, the need for research on this topic seems apparent. Using color dependent instructional materials with color blind, mentally retarded children may be detrimental.

On Knowing Books by Their Colors

1979 ◽  
Vol 48 (2) ◽  
pp. 479-488 ◽  
Author(s):  
Robert M. Boynton ◽  
Stanley Dolensky
Keyword(s):  
Color Vision ◽  
Recognition Task ◽  
Color Blindness ◽  
Test Period ◽  
Normal Color Vision ◽  
Abstract Stimulus ◽  
Color Cues ◽  
Stimulus Materials ◽  
Search And Recognition ◽  
Better Than

In a search and recognition task utilizing real-world objects, the usefulness of color cues is observed to depend upon the availability of alphanumeric information. Following a 45-sec. inspection of a randomly selected collection of 17 books, spread on a table with their titles exposed, subjects were asked to identify as many of these as possible during a test period beginning 3 min. later in which 17 decoys were also present. Some subjects wore glasses with red filters during the test and inspection periods. The color blindness thereby introduced did not impair their performance in comparison with control subjects who were able to utilize normal color vision. Moreover, the introduction of color during the test period impaired the performance of subjects who had been deprived of color cues during inspection. It was concluded that subjects paid attention mostly to book titles and for that reason did not use other cues, including color, to much advantage. In a second experiment, where titles were obscured, subjects with normal color vision performed much better than those who were made color blind during the inspection or test periods. The results of both experiments are generally consistent with predictions based on experiments which have used abstract stimulus materials.

scholarly journals Prevalence of Color Blindness in Undergraduates of Kathmandu University

2018 ◽  
Vol 56 (214) ◽  
pp. 900-903
Author(s):  
Reena Kumari Jha ◽  
Sukirty Khadaka ◽  
Yubina Gautam ◽  
Manisha Bade ◽  
Mukesh Kumar Jha ◽  
...  
Keyword(s):  
Color Vision ◽  
Cross Sectional Study ◽  
Color Blindness ◽  
Sectional Study ◽  
Cross Sectional ◽  
Color Blind

Introduction: Color blindness is X-linked recessive inherited disorder that occurs mostly in males and is transmitted through females. Many people with color blindness may remain undetected. Thus the present study aims to evaluate the incidence of color blindness among undergraduates of Kathmandu University. Methods: A cross-sectional study was conducted among 825 undergraduates, aged 17-25 years, from June to August 2018, in Kathmandu University, Kavre, Nepal. The Ishihara plates were used to evaluate the color vision of students under natural day light condition.Results: Study revealed that 24 (2.9%) undergraduates were color blind which include 24 male (5%) and no female. Among the color blind, five (20.3%), three (12.5%), two (8.33%) and 14 (58.33%) males were the victims of deuteranomaly, deuteranopia, protanomalia and total color blindness respectively. Color blindness is prevalent among the Brahmin 10 (3.9%), followed by Chettri 10 (2.72%) and Newar 4 (2.24%). Conclusions: Prevalence of color blindness is found to be higher in males 24 (5%) than females 0 (0%). Total color blindness is the most prevalent in our study. Screening enables the students to become aware of limitations and devise ways of overcoming them.

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