This study investigates the modulation of microsaccades by shifts of covert attention using a classical spatial cueing paradigm. Microsaccades, which are miniature eye movements that occur during fixation, are typically classified into tremor, drift, and microsaccades. The authors developed a new algorithm to detect microsaccades in two-dimensional velocity space, which allows for the identification of microsaccades as "outliers" in velocity space. In Experiment 1, participants fixated a central cue, which could be directional (left, right, or both directions) or neutral. The results showed that the presentation of the cue induced a decrease in the rate of microsaccades (inhibition) followed by an increase (enhancement) around 350 ms after cue onset. This modulation was observed for both directional and neutral cues. Additionally, the orientation of microsaccades shifted towards the cue direction during the enhancement phase. In Experiment 2, the cues were changed to color (red or green) instead of arrows, and the results showed a weaker modulation of microsaccade rate compared to Experiment 1. The orientation of microsaccades was also less affected by the color cues, with only slight distortions in the angular distributions. In Experiment 3, participants performed a simple fixation task without attention shifts, and the characteristic modulation of microsaccade rate was still observed. However, the angular distributions of microsaccades showed only small differences, indicating that the arrow symbols alone do not produce the modulations observed in Experiments 1 and 2. The authors conclude that microsaccades can be used to map the orientation of covert visual attention by analyzing their directional distributions. This finding challenges the traditional view of microsaccades as strictly low-level oculomotor phenomena and suggests that they may play a role in the processing of visual information.This study investigates the modulation of microsaccades by shifts of covert attention using a classical spatial cueing paradigm. Microsaccades, which are miniature eye movements that occur during fixation, are typically classified into tremor, drift, and microsaccades. The authors developed a new algorithm to detect microsaccades in two-dimensional velocity space, which allows for the identification of microsaccades as "outliers" in velocity space. In Experiment 1, participants fixated a central cue, which could be directional (left, right, or both directions) or neutral. The results showed that the presentation of the cue induced a decrease in the rate of microsaccades (inhibition) followed by an increase (enhancement) around 350 ms after cue onset. This modulation was observed for both directional and neutral cues. Additionally, the orientation of microsaccades shifted towards the cue direction during the enhancement phase. In Experiment 2, the cues were changed to color (red or green) instead of arrows, and the results showed a weaker modulation of microsaccade rate compared to Experiment 1. The orientation of microsaccades was also less affected by the color cues, with only slight distortions in the angular distributions. In Experiment 3, participants performed a simple fixation task without attention shifts, and the characteristic modulation of microsaccade rate was still observed. However, the angular distributions of microsaccades showed only small differences, indicating that the arrow symbols alone do not produce the modulations observed in Experiments 1 and 2. The authors conclude that microsaccades can be used to map the orientation of covert visual attention by analyzing their directional distributions. This finding challenges the traditional view of microsaccades as strictly low-level oculomotor phenomena and suggests that they may play a role in the processing of visual information.