This review focuses on the use of quantitative eye-movement recordings in the diagnosis of ophthalmologic and neurologic disorders and in the investigation of the pathophysiologic mechanisms of and possible treatments for these disorders. Recently developed methods for measuring eye movements about all three axes of rotation (horizontal, vertical, and torsion) are emphasized. These techniques are providing important insights into the basic physiology of eye-movement control and into the mechanisms of ocular motor disturbances in which torsion plays a significant role.