Prevalence of congenital colour blindness among Inuit in East Greenland.

PURPOSE: To establish whether congenital colour blindness among males is still rare in Inuit (Eskimos) as indicated previously in 1893 and 1930, especially in East Greenland, as demonstrated by Erik Skeller in 1950. METHODS: The study was comprised mainly of school children. 540 Inuit in East Greenland were compared to 545 controls in East Greenland and Denmark examined by three sets of pseudoisochromatic plates (Ishihara 1932, original plate used by Skeller), Ishihara (1994), and standard P.P. 2 part Igaku-Shoin (1994). RESULTS: Only 1.0% of male Inuit (3/290) are colour blind, a significantly lower incidence than the 8.7% among Danish males in Denmark (15/173). The prevalence was the same in the three control groups, Danes in East Greenland, immigrants and Danes in Denmark. Deuteranopia is the most common type. Females showed the same low prevalence in all four groups. MAJOR CONCLUSIONS: Colour blindness is still remarkably low among Inuit in East Greenland as compared with the present three control groups.