Changes in electroretinogram oscillatory potentials during dark adaptation

Purpose: To investigate changes in the oscillatory potentials (OPs) of electroretinograms (ERGs) during dark adaptation (DA). Methods: ERGs were recorded from ten normal subjects. Following 15 min of light adaptation, ERGs were recorded every 30 s for 20 min to follow the changes in the OPs during the course of DA. A 20-ms., 560-nm rectangular pulse of light was presented at 3.3 Hz to elicit the ERGs. Results: The latencies of Opt and OP2 did not change significantly, but the amplitudes decreased slightly during DA. OP3 was not observed at 30 s, but appeared after 1 min of DA between OP2 and OP4. Similar results were obtained with stimulus durations of 10 to 100ms in 10-ms steps. The amplitude of OP3 increased to 10min of DA and then plateaued. Conclusion: The characteristics of OP3, which increases during DA, indicate that it is probably related to rod activity.