Incidence of red-green color blindness in the Basque population

The incidence of red-green colour vision defects was studied in a sample of 392 Basque students (174 males and 218 females), using the Ishihara test cards (1987). The frequency of red-green colour blindness was 4.02 percent in the males and 0.46 percent in the females. The colour blindness frequencies found among males are within the range of other Spanish samples. Nevertheless they are lower than the values reported in other European populations.