Prevalence Of Color Vision Deficiency Research Articles

Prevalence of Colour Blindness in Young Jordanians

Colour blindness is one of the common genetic disorders observed in all human populations. It is a sex-linked recessive trait. The genes are located on the X chromosome within the Xq28 band. 1,418 university students (1,200 female and 218 male) from Zarka Private University and the Hashemite University were randomly selected and tested for congenital red/green colour blindness, by using Ishihara pseudo-isochromatic colour plates. A total of 23 individuals were found to be colour blind. In females, 4 students (0.33%) were colour blind: 1 of them showed protanomalia, 1 protanopia and 2 deuteranomalia. In males, 19 students (8.72%) were colour blind: 4 showed protanomalia, 3 protanopia, 8 deuteranomalia and 4 deuteranopia. The allelic frequencies of the colour vision gene were found to be 0.087 in males, 0.003 in females and 0.016 in the total population. Studies on colour blindness in Jordan are very few; this population-based investigation is meant to fill a gap in this field.

Hypertension and Color Blindness in Young Men

Medical data from Selective Service registrants born from 1939 to 1941 were studied in Oregon and Colorado. Among 29,119 registrants with medical information (41.3% of all registrants), 1,073 (3.6%) had definite hypertension, and 1,226 (4.2%) had some type of color blindness. In both states, there was a highly significant association between the prevalence of hypertension and the prevalence of color blindness. Thus, definite hypertension was present in 6.0% of color clind individuals but in only 3.6% of those with unimparied color vision, while color blindness occurred in 6.8% with definite hypertension, in 5.8% with borderline hypertension, and in only 4.0% with normal blood pressure. The data did not differentiate among types of color blindness, and the reason for the association is not yet evident.

Was Homer Colour-Blind?

UPON reading Dr. Pole's two papers (NATURE, vol. xviii. pp. 676, 700) my first feeling was to ask: “But how could ‘The blind old man of Scio's rocky isle’ know anything at all about colour?” Presuming, however, that the tradition of his blindness might be unwarranted, and further, that it may be a mistake to suppose, as many do, that the “Iliad” is a collection of rhapsodies by different poets, I again asked myself: “Are there in Homer more anomalies in the nomenclature of colours than may be accounted for by the vague use of words? Are there more than we should find in this country among uneducated men of the labouring class?” About two years ago I made extensive inquiry as to the prevalence of colour-blindness among children, and in the village schools of this part of Somersetshire I found that the girls could name the neutral as well as the other tints readily and correctly, but that many of the boys had but about half-a-dozen words to use, and would refer orange to red or to yellow, and purple to brown or to blue, merely for want of terms; for they could match the test papers with other papers, or with the girls’ dresses.