Pupillodynamics with repetitive identical stimulations

The influence of repetitive identical stimulations on the pupillary reactions was examined using a modified TV-pupillograph. In nine cases two series of six stimulations were performed. During the first series the interval between each stimulation was 10.5 seconds, during the other series it was 1.5 seconds. A step-by-step decrease of the original pupillary diameter was found during the sequence of stimulations. The contraction amplitude remained unchanged from the first to the last stimulation in each of the two series. However, in using the shorter interval the amplitude was significantly lower.