Figure 8. Ganzfeld and focal ERGs in untreated and light-treated eyes. A: The a- and b-wave amplitudes of the scotopic Ganzfeld electroretinogram (ERG) and B: the focal ERG were not statistically significantly different between the untreated (n=9) and light-treated (n=6) eyes, Note that a- amplitude is usually negative but is recorded as a positive absolute value for ease in comparison.