Some questions concerning electroretinographic response and its variability

Changes in retinal potential take place when the eye is adequately stimulated. This evoked response, the electroretinogram (ERG) is recorded in vivo by placing an electrode on the cornea, while the reference electrode is grounded elsewhere. In spite of a great deal of work in this field, the very meaning of ERG, in the frame of visual process, is not yet wholly understood. The present paper produces some data which show that the plot of visual performance vs. time, during the course of the day, runs parallel to that of the size of ERG. The meaning of this finding is discussed, by making reference to the electrical analog of the recording circuit, in terms of lumping approximation.