If a stimulus of large subtense and low intensity is presented to the dark adapted eye, the resulting ERG-response shows several fast positive components, followed by a slow negative deflection. The number of the positive components depends mainly on the duration of the flash. The first is hardly affected by changes in the intensity range studied, a linear dependency and the letter therefore determine the amplitude and shape of what is called the normal scotopic b-wave. This linearity also accounts for the excellent responses one can obtain at intensity levels very near the differential visual threshold.
Samenvatting