Further Studies on Acquired Deficiency of Color Discrimination*

Abstract

First, the relationship between color discrimination, sex, and age is studied by giving the 100-Hue Test to 480 unselected subjects between the ages of 10 and 64. The mean total score of the 20–24-yr group is significantly lower than that of all other groups; the mean partial scores are always highest in the blue–green and red sections of the test and this tendency is accentuated in the age groups with a higher mean total score.Second, a reproduction of the senile decrease of color discrimination is attempted by fitting young subjects with filters, which absorb more or less selectively the rays of shorter wavelengths and which have several total optical densities; the effect of these filters is studied by means of the AO H-R-R and Farnsworth pseudoisochromatic plates, the Panel D-15, the 100-Hue, the Tritan-Plate Tests, and the anomaloscope.Third, some 500 eyes affected by different diseases are examined by means of a diagnostic set including the Ishihara, AO H-R-R, and Farnsworth pseudoisochromatic plates, the Panel D-15 Test, the 100-Hue Test (the interpretation of which was subjected to some modifications), and the anomaloscope. Occasionally a complementary set is used in order to get further information about the photopic spectral curve of relative luminous efficiency and about the spectral mixture functions. Accordingly, the acquired deficiencies of color discrimination are classified into four types: (1) a type in which a prominent axis of deterioration of color discrimination cannot be determined—This type is ill defined and principally occurs in some cases of macular cysts and of toxic amblyopia; (2) a Type I of acquired red–green deficiency, which is characterized by a progressive shift of the photopic spectral curve of relative luminous efficiency towards the shorter wavelengths, till it becomes identical to the normal scotopic function—It occurs chiefly in juvenile macular degeneration and in some other chorio-retinal degenerations; (3) a Type II of acquired red–green deficiency, in which the photopic spectral curve of relative luminous efficiency remains normal—It occurs in nearly all diseases of the optic pathways; (4) an acquired blue–yellow deficiency, which can be associated with a shift of the photopic spectral curve of relative luminous efficiency towards the shorter wavelengths and which occurs in most chorio-retinal diseases.Nevertheless, the acquired deficiencies of color discrimination are only seldom as well outlined as the congenital ones.