•^50 10 



061 081 



Fig. 150. — Perimeter chart indicating the average fields of vision for blue, red, and 

 green compared with white (gray). Right eye: The outlines of the color fields are repre- 

 sented as smooth since the chart is an average from many determinations. As a matter of 

 fact, in each individual the outline is highly irregular. Nonnally green (bright green) is the 

 smallest field, green objects outside the limit appearing yellow and farther out colorless 

 (gray). 



Fig. 151. — Perimeter chart showing the highly restricted color fields in the left eye 

 of a typical case of so-called red-green color blindness. The ability to distinguish red and 

 green, by whatever characteristics of intensity or color they possessed extended for a very 

 short distance outside the fovea. It is interesting that the ability to distinguish blue was 

 Lq this case limited as compared with a normal eye. 



355 



