Four Eye Movement Control Systems

Terry Bahill
Systems and Industrial Engineering
University of Arizona
Tucson, AZ 85721-0020
terry@sie.arizona.edu
© 1999-2004 Bahill

Ancient poets and romantics have said that the pupils are the windows to the soul: modern bioengineers say that eye movements are windows to the brain. I have been studying the brain through this window, perhaps I should say windows because there are four basic types of eye movements: saccadic eye movements that are used for reading or scanning a scene, vestibulo-ocular eye movements that are used to maintain fixation during head movements, vergence eye movements that are used when looking between near and far objects, and smooth pursuit eye movements that are used when tracking moving objects, such as airplane.
These four types of eye movements are produced by four independent control systems. Their dynamic properties, such as latency, speed, and high-frequency cutoff values, are different. They are produced by different areas of the brain, and they are affected differently by fatigue, drugs, and disease.

Reference [74]. This lecture is suitable for bioengineers, human factors engineers, or medical students, especially neurology or ophthalmology specialists. It requires only a chalkboard. This talk takes one hour.