Some characteristics of the C-wave of ERGs recorded by a pair of electrodes on the cornea and sclera.

Light-evoked responses of the rabbit retina in situ were recorded between the electrode on the longitudinal line of the nasal (positive) and the electrode on the opposite longitudinal line of the temporal side (negative). The c-wave was negative and the a-, b-wave was reversed when the negative (temporal) electrode was closer to the corneal center than the positive (nasal) electrode. The c-wave decreased its amplitude as the positive electrode came to the same latitudinal position as that of the negative one. Then, the c-wave was cancelled out in appearance on the recordings. When the negative electrode moved further into the posterior pole, the polarities of the c-wave as well as of the a-, b-wave were returned to those of routine ERGs.