Changes in ERG b-wave and Oscillatory Potential in Relation to the Dark Adaptation and Light Adaptation Time

ABSTRACT

Authors studied characteristics of ERG b-wave and oscillatory potential, which can be applied to ERG protocol for clinical purposes. Following conclusions were obtained from the ERG test performed on 20 normal men(40 eyes) during dark adaptation and light adaptation time, under the conditions where other factors were equal. 1. In the scotopic ERG test, 88%(364/414uv) of maximum b-wave amplitude in 30 minutes were obtained in first 1 minute of dark adaptation. By using this shortening scotopic protocol for the acquired retinal disease, sufficient result can be expected without the over 20 minutes dark adaptation. 2. In the photopic ERG test, if over 30 minutes dark adaptation time were given, it would take at least 15 minutes to reach the regular initial photopic value. Therefore, it is recommended that photopic ERG test be done before the scotopic ERG test. 3. In the oscillatory potential test, light adaptation time has little effect on summed photopic oscillatory potential amplitudes and implicit time. Summed scoto pic oscillatory potential amplitude reaches the highest 1 minute after the dark adaptation. Therefore, it is recommended that to obtain higher amplitude and more sensitive test result, oscillatory potential test be done 1 minute after the dark adaptation.