EyeMMV toolbox: An eye movement post-analysis tool based on a two-step spatial dispersion threshold for fixation identification

Eye tracking is a tool in scientific fields addressing the study of human vision and perception. Eye movement analysis produces indications for the understanding of human vision. The human eyes make successive movements during the observation of a visual scene or display. A fixation occurs at the moment when the eyes remain relatively stationary in a position (Poole & Ball, 2005). This moment is characterized by the miniature movements of tremors, drifts and microsaccades (Martinez-Conde, Macknik, & Hubel, 2004). In practice, the analysis considers as given fact that fixations happen in discriminant points having limited duration and dispersion. The process of identifying fixations among eye movement protocols can have a great impact on higherlevel analysis (Salvucci & Goldberg, 2000). The result of the process of identifying fixations is typically a sequence of the position, the onset time and the duration of each fixation (Salvucci, 2000).