[General criteria of working ability in subjects with color vision defects]

A correct evaluation of the colour vision is important to make decisions concerning the recruitment in numerous occupations that require colour discrimination. In order to identify valid pre-employment colour vision testing methods, tests actually used and in particular the Ishihara test are considered. After a careful examination we conclude that candidates who pass the Ishihara test have sufficient colour perception to meet ordinary needs and further trade test are not necessary. Nevertheless we do not consider sufficient to rely on the Ishihara test alone to reject a candidate. The diagnostic algorihm proposed is recommended in pre-employment medical examinations for distinguishing people with normal colour vision, slight or sever colour deficiency.