Repeated Measurements and Session-Spacing Effects on Critical Flicker Frequency

To evaluate the effect of session replication and the effect of the duration of the interval between sessions on CFF, three groups different in the methods of spacing sessions were tested for 10 sessions. A significant interaction effect was observed between interval durations and session replications. The group that was tested daily for five consecutive days showed a consistent elevation in threshold after the first two sessions, while the other two groups showed relatively uniform threshold scores over the 10 sessions.