During fixations, eye is not still but drifts irregularly {drift, eye} {eye drift} through several minutes of arc, over several fovea cones.
During fixations, eye is not still but moves in straight lines {microsaccade} over 10 to 100 fovea cones.
Eyes scan scenes {scanning, vision} in regular patterns along outlines or contours, looking for angles and sharp curves, which give the most shape information.
During fixations, eye is not still but has tremor {eye tremor} {tremor, eye} over one or two fovea cones, as it also drifts.
After fixations lasting 120 ms to 130 ms, eye moves {saccade}|, in 100 ms, to a new fixation position.
brain
Superior colliculus controls involuntary saccades. Brain controls saccades using fixed vectors in retinotopic coordinates and using endpoint trajectories in head or body coordinates [Bridgeman et al., 1979] [Bridgeman et al., 1981] [Goodale et al., 1986].
movement
People do not have saccades while following moving objects or turning head while fixating objects.
transformation
When eye moves from one fixation to another, brain translates whole image up to 100 degrees of arc. World appears to stand still while eyes move, probably because motor signals to move eyes cancel perceptual retinal movement signals.
perception
Automatic saccades do not noticeably change scene [Akins, 1996] [Blackmore et al., 1995] [Dmytryk, 1984] [Grimes, 1996] [O'Regan et al., 1999] [Rensink et al., 1997] [Simons and Chabris, 1999] [Simons and Levin, 1997] [Simons and Levin, 1998] [Wilken, 2001].
Brain does not block input from eye to brain during saccades, but cortex suppresses vision during saccades {saccadic suppression}, so image blurs less. For example, people cannot see their eye movements in mirrors.
1-Consciousness-Sense-Vision-Physiology
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Date Modified: 2022.0225