2. The largest of the fixational eye movements, carrying an image across dozens to several hundred of the eye's photoreceptor (light-detecting) cells, including cones for detail and color vision and rods for low-light and peripheral vision.
People naturally hold microsaccades at bay momentarily when they perform precision tasks; such as, when shooting a rifle or when threading a needle.
The largest voluntary eye movements
When the eyes focus on something, they still jump imperceptibly in ways which turn out to be essential for seeing.
For decades, scientists have debated the purpose, if any, of these so-called fixational eye movements, the largest of which are called microsaccades. It has been demonstrated that microsaccades engender visibility when a person's gaze is fixed and that bigger and faster microsaccades work best.
Microsaccades may also shed light on subliminal thoughts. Recent research suggests that the direction of microsaccades, is aimed toward objects to which people are unconsciously attracted, no matter where they are actually looking.
Microsaccades alter the responses of other cells in the visual system. Without these movements, visual neurons would adapt to the unchanging stimulus by decreasing their activity resulting in fading vision.