[Characteristics of the EOG potential changes generated by saccadic eye movements of large amplitude]

The time curve of the electrooculogram (EOG) as applied to clinical diagnosis is measured as the changes in the standing potentials around the eyes when a subject performs saccadic eye movements of constant amplitude. If the characteristics of these potential changes caused by the eye movements are known, the time curves of EOG can be derived from the potential changes generated by saccadic eye movements of random amplitude, by transforming the measured potentials into the exact values corresponding to the constant amplitudes of saccades. We have already reported that the characteristic curves of EOG are proportional to the angles of the eye movements within +/- 20. However, Fenn and Hursh reported that the characteristics of saccadic eye movements for larger amplitudes up to about 80 degrees were sinusoidal functions. Other workers have reported linear relations of the characteristics of EOG. In this report we attempted to clarify whether the characteristics of EOG were linear or sinusoidal. From our experiments it became clear that the characteristics of EOG could be approximated to straight lines up to about 80 degrees (visual angle).