Induced Pupillary Oscillations

Abstract

The maintenance of a slit-lamp beam on the pupillary margin induced a series of pupillary oscillations of regular rhythm and good amplitude with a mean rate of 68.9 /min. in a series of 60 healthy subjects between the ages of 17-36 yrs. An increase in light intensity resulted in an increased rate, and vice versa. Preliminary dark-adaptation caused an increased rate during the first 5 min., and light adaptation caused an initial decrease. Exercise produced a rapid decrease in rate with a return to normal within 10 min. It is suggested that all the above changes in rate may be dependent on changes in pupil size and that there is a significant negative correlation between pupil size and frequency of oscillation. There is a significant positive correlation between resting pulse-rate and frequency of pupillary oscillations. Age, sex and iris color do not appear to affect the rate. There is no evidence of pupillary fatigue even after 200 continuous oscillations.