The Effect of Display Luminance Conditions upon Pupillary Response

Two experiments were carried out to investigate the relationship between display luminance conditions and pupillary response. The first experiment attempted to determine whether or not peak luminance or integrated luminance played a greater role in determining pupil diameter. The result indicates that the pupil diameter to an irregular luminance field is biased significantly in the direction of the peak luminance. This suggests that the lighter of the two items, either background or the character, will essentially control the pupil diameter, thereby negating any effect on pupil size due to positive versus negative image. The second experiment attempted to investigate the effect of luminace ratio, between source document and screen, on pupil diameter and subjective fatigue. The result indicates that the difference between pupil diameter to source document luminance and screen luminance has more to do with the peak luminance of the screen than with the integrated luminance. Such a difference, even in the case of negative image displays, is not very large. This suggests that proposed lighting differences based on image polarity or recommendations of positive image polarity do not appear to be warranted