How normal are "normal" square wave jerks?

Fifty normally sighted young subjects underwent horizontal electro-oculographic (EOG) examination to investigate fixation stability of the saccadic system. The number of square wave jerks (SWJ) and saccades per minute were calculated in three clinically used test conditions: (1) with a fixation point; (2) in darkness; and (3) with eyes closed. SWJ were recorded in all conditions. The highest number of SWJ per minute were found in darkness and with closed eyes. The analysis of the findings shows a range of normalcy for these three clinically used EOG conditions from which pathology can be inferred.