The head of the experiment person is placed that way, that the light is reflected into a camera, in which a film is slowly moving. The gained record is the eye movement registrated in time. The method was worked out by Dodge . The saccadic movement is the coordinated movement of both eyes, therefore it is usually enough to record the movement of only one of the eyes. The movement starts rapidly and ends rapidly.
Individual differences are really small .
The function of saccadic movements is to move the eye from one fixation point to the another. Information acquirement is only possible during the fixations, it is not possible during the movement. During a saccadic jump the whole field of sight slides through the retina, and it slides very fast, but the arising quick, faded picture is insignificant in the perception. We learned not to percieve this, as we learned not to percieve the blink of the eyelashes. Although if something is in sharp contrast to the background we can percieve something from it during saccadic movements.