Incidence Of Color Blindness Among Some Endogamous Groups Of Bathinda District, Punjab

Abstract

To find out the incidence of sex-linked defective color vision in people of Bathinda district in southern Punjab, a survey was planned among the school going boys using standard Ishihara’s Color Plates Chart. The present study was conducted on a total of 1,002 individuals belonging to 9 caste,11 backward caste and 5 scheduled caste endogamous groups, as well as a few from Muslim and Christian religious groups. In the total individuals screened as many as 34 cases of red-green color blindness and 3 of total color blindness were detected. All the red-green color blind subjects were found to be of deutan type, comprising 8 strong and 26 mild cases. No protan individual was detected in the present survey. Of the 27 endogamous groups tested, 16 groups showed absence of the trait while the incidence in remaining groups of the castes, backward castes and schedule castes were in rather similar and broad ranges between 0 to 6.7%, 0 to 6.3% and 0 to 4.7% respectively. Besides, in each of these 3 caste groupings, 1 total color blind subject was found. Compared to some initial studies on color blindness available from Punjab(average 5.2%),the present and some other recent surveys provide comparatively lower estimates of all trait (average 3.22%) which is found to be very close to that of U.P.(3.28%) and Delhi (3.15%) suggesting similarities in this genetic trait among populations of these states of the region. While in 249 populations on the North-Western Indian region so far tested the average incidence of color blindness was calculated to be 3.98%.To fully appreciate the true variation of this genetic trait and also to complete the genetic map of people of people of Punjab, further studies, are required.