The possible changes in pupillary psychosensory restitution (PPR) occurring with age were investigated by means of pupillography. Measurements of pupillary size and motion were obtained from a group of 94 ostensibly normal, white, male and female subjects ranging in age from 7.5 to 90.8 years. The results indicate (1) statistically significant differences in the PPR occurring with age as reflected in a progressive decrease in mean maxima and minima pupil diameters, extent of constriction, and response velocity; (2) in general, a progressive increase in the variability of the response with age; (3) a significant, linear, and negative relationship between age and the PPR, the correlation coefficients ranging from -0.53 to -0.72 (dƒ=91); (4) a significant relationship between pupil size in the dark and in the light, the correlation coefficient being 0.92; (5) that the relationship in (4) is not attributable to the accompanying decrease in size, since the partial correlation coefficient for the partial correlation between pupil size in the dark and in the light, with the effect of age held constant, is 0.86; and (6) that sex and eye color are not factors in this study. Autonomic nervous system response (revealed in the PPR) and age are variables which should be considered in investigations on pupil size and motion, intensity discrimination, brilliance-function, relative luminosity, and visual fields.
LILLIAN S. KUMNICK, "Pupillary Psychosensory Restitution and Aging," J. Opt. Soc. Am. 44, 735-740 (1954)