Background: Colorblind disability causes difficulties for people in daily life. Derived from the critical requirement to detect the patients in order to help prevent inappropriate careers, especially careers related to transportation, this research aim to determine the situations and the distributions of different types of visual disabilities.
Materials: 1174 students (787 boys and 387 girls) including 2 groups: occupation group and transportation group were tested with ISHIHARA chromatic plates for colour vision deficiencies (CVD) (CVD iclude the total colour blindness, red- green blindness, red-blindness, green- blindness).
The results are showed as follow:
(i) Frequency of CVD boys among boy group is 4.70%;
(ii) Frequency of CVD girls among girls group is 2.58%;
(iii) In boy group, among 3 types of red- green blindness, the green-blindness has the higher frequency (3.18%) comparision with these ones of the red- green blindness and red-blindness. The total colour defiency was hardly;
(iv) Frequency of CVD students among occupation group is 4.15%;
(v) Frequency of CVD students among transportation group is 3.83%.