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 OP1 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 100 ms in 10-ms steps. The amplitude of OP3 increased to 10 min of DA and then plateaued.

CONCLUSION

The characteristics of OP3, which increases during DA, indicate that it is probably related to rod activity.