[The history of research in color perception as a key to understanding various forms of congenital defects in red-green perception].

It is accurate to date the first scientific report about colour-deficiencies on 1777. Earlier descriptions may be followed up to the end of the 17th century. But usually it is only mentioned, that mistakes had happened. Huddart 1777, however, reported for the first time, that more than one person was involved in a family and that demonstrations of coloured ribbons helped to find out which colours became confounded. The famous self-observation of Dalton contains the assortment of individually combined silk-threads, which is an anticipation of subsequent arrangement-tests. Goethe developed a systematic arrangement-test of self-made small coloured targets with colours out of his own colour-wheel. A. Seebeck was the first who--using the spectrum for examination--found out that a special group of subjects showed a shortening of the spectrum at the red end. From this result Helmholtz concluded the existence of two types of red-green blindness. This new argument for the trichromatic organisation of our colourvision was the basis for the statement of the three types: protanopia, deuteranopia and tritanopia (v. Kries, A. König). Rayleigh later on succeeded in finding out anomalous trichromats following preparatory examinations of Maxwell. Nagel has the merit to have analysed protanomaly and deuteranomaly using the anomaloscope constructed by himself. Side by side with the spectral colour-tests pseudoisochromatic plates were developed for diagnostic purposes, at first thought out and introduced by Stilling and in the meantime used in many variations.