Academic journal article Iranian Journal of Public Health

Prevalence of Red-Green Color Vision Defects among Muslim Males and Females of Manipur, India

Academic journal article Iranian Journal of Public Health

Prevalence of Red-Green Color Vision Defects among Muslim Males and Females of Manipur, India

Article excerpt


Background: Color blindness is a common X-linked genetic disorder. However, most of color blinds remain undetected due to absence of proper screening. Our study was to determine the prevalence of red-green color vision defects among Manipuri Muslim males and females. The study could help in decreasing birth of children with this disorder as Muslims commonly perform consanguineous marriage among themselves.

Methods: Unrelated individuals of both sexes (Male-1352, Female-1302) belonging to six different populations were randomly selected and screened for red-green color vision defects using the Ishihara (pseudo-isochromatic plates) test from the area of Imphal East and Imphal west districts of Manipur, which is a small hilly state, situated in the north eastern extreme corner of India sharing an international boundary with Myanmar (Burma).

Results: About 8.73% of males and 1.69% of females were found to be color blind. Among six different populations studied the males of Meitei population shows the highest frequency i.e. 14.93% while Naga population shows the least frequency of 3.75%. Among females, Meitei population again shows the highest frequency of 2.5% and least frequency is shown by Mughal and Naga populations 0.00% as not a single female color blind was found.

Conclusion: Present study shows higher prevalence rate of color blindness as compared to other reported rates of India. Deuteranomaly cases occur in higher percentage than other types of color blindness. The higher prevalence rate observed in Muslims may be due to the hidden effect of consanguineous marriages.

Keywords: Color blindness, Ishihara color test, Manipur, Allele frequency, Protan, Deutan, India


The ability to have trichomatic vision distinguishes humans from non-primates. However, inherited congenital color vision defects (CVD), comprising a number of distinct disorders collectively, are rela-tively common and is often a handicap in everyday life. There is no treatment for color-blindness, nor is it usually the cause of any significant disability. "Color blind" is a term of art; there is no actual blindness but there is a fault in the development of one or more sets of retinal cones that perceive col-or in light and transmit that information to the op-tic nerve. It is a sex-linked condition. The genes that produce photo pigments are carried on the X chromosome; if some of these genes are missing or damaged, color blindness will be expressed in males with a higher probability than in females be-cause males only have one X chromosome (in fe-males, a normal gene on only one of the two X chromosomes is enough to yield the needed photo pigments) (1-4). A color-blind person suffers from certain problems in different fields, like generally they are unable to interpret some chemical reac-tions and the chemical testing kits (5). Color vision deficiencies were detected in 8% of Dutch gastro-intestinal endoscopist and affects endoscopist's di-agnostic skill. Using a literature search, the results indicated the prevalence of color vision deficiency (CVD) in the medical profession and the medical skills (6). Clinical laboratory testing is crucial to de-tecting and diagnosing diseases. Laboratory employ-ees as technicians and technologists examine and analyze the chemical content of fluids, tissues and cells, look for microorganisms, match for transfu-sions, and use automated equipment and sophisti-cated, microscope and cell counters. Lab employees also maintain glasswares, instruments, logs and rec-ord books, keys to success in this vocation. Color blindness can be a prohibitive factor in some cases (7). Thirteen percent of histopathologist and 10% of medical laboratory technologists in the United Kingdom have deficient color vision which makes more errors in slide interpretation than those with normal color vision. They concluded that histopathologists and medical laboratory technolo-gists and technicians should have their color vision tested (8, 9). …

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