Familial appraisal of colorblindness in school children of an Indian population

: A total 2000 unrelated school children were screened for colorblindness in Vishakhapatnam, India. Whether the protan and deutan defects are the result of mutations at one locus or at two loci has not been completely resolved, although the evidence favors two discrete loci. The investigation was extended to the families of the 40 color vision anomalous children to study the descendance patterns of these two loci. The importance of these observations are discussed.