1. Movements of the eyes
The muscles were of necessitie provided and given to the eye, that so it might move on every side; for if the eye stoode faste and immoveable, we should be constrained to turne our head and necke (being all of one peece) for to see; but by these muscles it now moveth it selfe with such swiftness and nimbleness, without stirring of the head as is almost incredible...
A. Du Laurens (1599) A Discourse of the Preservation of Sight: of Melancholike Diseases; of Rheumes, and of Old Age

2. One degree from the center of the fovea (1 degree = width of finger at
arm’s length), visual acuity is less than half of what it is in the fovea.
So saccadic eye movements shift the center of gaze around the image. 1 2
0.1° 1°
10°
Eccentricity

3. Vision is an active process. Binocular vision afforded by aligning
the eyes provides depth signals necessary for capturing things in
the environment.

4. Six extraocular muscles rotate the
eyes.
Types of movements of the eyes
Gaze shifting
Saccade
Pursuit
Vergence
Gaze holding
Vestibular-ocular reflex
Optokinetic reflex

5. A neuron producing movements of the eyes

6. Brainstem Saccade Generator
Eye position
Pulse
Step
Force
Oculomotor neuron
100 msec

7. Brainstem Saccade Generator
Eye position
Oculomotor neuron
Tonic neuron
Medium lead burst neuron
“Neural Integrator”
“Motor error”
“Eye velocity”
"Where"
"When"
Omnipause neuron
100 msec