DISCUSSION

Abstract

Many studies on the relation between the eye fatigue and levels of illumination have carried out in Japan since 1938, as Fig. 2 showing some results of them. The results of those studies indicate different values of illum. levels as the most favarable level of illumination for the visual tasks.On the other hand many studies on the relation between the visual acuity and levels of illumination have carried out. Most of all results of those studies on the visual acuity show that the visual acuity becomes better with the increasing of levels of illumination, and as we know, those results have adopted in the modern illum. eng. technique.Comparing the study on the eye fatigue with that of the visual acuity, we notice that the study on the eye fatigue indicates often the existence of the most favarable level of illumination, as shown schematically curve B in Fig. 1, and incompatible with this fact, almost of all results of studies on the visual acuity never indicate the existence of the best level of illnmination, as curve A in Fig. 1. indicates.This paradox occurs, I believe, owing to the quality of the illumination, because it would be much easier to make the quality of illumination better at the target for visual acuity measurements than the space of visual tasks, the quality means the glare, the contrast distribution in the visualfield and the color temperature of illuminants. I assumed on this paradox that the curves of full lines in Fig. 1 would removed toward the dotted lines by the improvement of the quality of the illumination.This study by Dr. Matsui interested me very much in the meaning of the above mentioned matter, and results of this study makes certain of my hypothesis on that paradox.