An alternating checkerboard pattern subtending a visual angle of 25 min arc is capable of eliciting remarkably high amplitudes of visually evoked potentials (VEP) outside a visual angle of 2.5 degree. These contributions cannot be neglected when evaluating a VEP response obtained with a larger field of stimulation. When the retina is consecutively stimulated by concentric frame-shaped stimuli, the algebraic sum of all single cortical responses augmented the cortical response obtained when stimulating the whole field simultaneously by approximately 30%. This finding may be explained by the inhibiting interactions within the receptive field organisation of the retina.

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Enucleated bull's eyes were perfused with blood and ERG recorded, with special attention paid to the slow components. When the blood flow was interrupted, the ERG components vanished in the following order: b wave, c wave, off-effect (d wave), and a wave. When the perfusion was continued afterward, we saw a variation in the standing potential that hinted at the biochemical activities causing slow electrical potentials of the retina.

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A soft lens material was tested in respect to its usefulness for corneal ERG electrodes. Recordings of a comparable quality to those achieved by hard low-suction corneal lenses are reported. Lesions of the cornea and the strain for the patients during the procedure were considerably diminished by the soft, easily tolerated electrode.