Scoring the Farnsworth-Munsell 100-hue for vocational guidance

We considered whether the color discrimination of mild color defectives scoring < or = 100 is the same as that of normals. We analyzed the FM 100-hue results of 126 normals and 94 congenital color defectives retrospectively by considering the Total Error Score (TES) and individual cap errors (error profiles). A TES of 100 passes 95% of normals and 24% of congenital color defectives. The error profiles of some of the mild defectives who pass show abnormal peaks along a red-green axis. An error > or = 5 in these regions is a good indicator of abnormal color discrimination. Some 30% of mild defectives (TES < or = 100) have limited hue discrimination in the red-green domain, so both the TES and error profiles need to be considered when providing vocational guidance.