Microsaccade

Microsaccades are tiny, involuntary saccadic eye movements, typically well under 1 degree of visual angle, that occur several times per second even during deliberate steady fixation. Martinez-Conde, Macknik, and Hubel (2004) reviewed evidence that these fixational eye movements are not measurement noise but a functional requirement of vision: because retinal neurons adapt to unchanging input, a perfectly still eye would cause a fixated image to perceptually fade, and microsaccades continuously refresh the retinal image to prevent that fade. Microsaccade rate also tracks covert shifts of attention even when gaze position barely changes.

Reference: Martinez-Conde, Macknik & Hubel, 2004. The NeuroRank implementation holds the canonical form and scales interference via task-irrelevant stimulus density.

1. Holding a static pre-aim angle for several seconds without the target silhouette perceptually fading, a function fixational eye movements perform automatically below conscious awareness.
2. The brief, near-imperceptible gaze shifts that occur while a player stares at a fixed choke point in CS2, still refreshing the retinal image the whole time.
3. Micro-adjustments in an aim trainer's static flick-and-hold drills, where the eye never truly stops moving even when the crosshair appears rock steady.

NeuroRank does not resolve eye movement at the microsaccade scale, since a browser-based combine has no eye-tracking hardware. The construct is included here because it underlies the baseline visual stability assumption behind every fixation-dependent module, including Aim and Flicker.