Microsaccades are a kind of
fixational eye movement. They are small, jerk-like, involuntary
eye movements, similar to miniature versions of voluntary
saccades. They typically occur during prolonged visual
fixation (of at least several seconds), not only in humans, but also in animals with
foveal vision (primates, cats, etc.). Microsaccade amplitudes vary from 2 to 120
arcminutes. The first empirical evidence for their existence was provided by
Robert Darwin, the father of
Charles Darwin.