This paper reports on the potential roles and importance of electrooculography (EOG) for mathematics educational neuroscience research. EOG enables accurate measurements of eye-related behavior (i.e., blinks & movements) by recording changes in voltage potentials generated by eye-related behavior. We identify and discuss three main uses of EOG. First, EOG provides insights into cognitive function. Secondly, it is used to attenuate eye-related artifacts in electroencephalography (EEG). Thirdly, EOG serves as a helpful means for calibrating covert brain activity with overt behavior. We provide an overview of the first two application areas, and we illustrate the third application using an example data set capturing an "aha moment" in our research in the area of mathematical problem solving.. (Contains 10 figures.)