The eyes never remain completely still. Even when attempting to maintain our gaze stable looking at a small target, fixational eye movements keep the eyes in constant motion. Given the simplicity of the task and the rich dataset that can be obtained, the interest in fixational eye movements has grown in multiple research and clinical fields. First, this chapter reviews the general classes of eye movements and how they may contribute to the main two components of fixational eye movements: drifts and microsaccades. While microsaccades are considered to be part of a continuum with saccades, drift results from a combination of all other smooth eye movements, such as vestibular ocular reflex, smooth pursuit, and vergence. Then, it discusses the methods used to analyze fixational eye movements and what are the typical parameters of interest and some considerations on how they should be measured. Finally, it describes how fixational eye movements are altered in patients affected by different degrees of vision loss, by movement disorders, or by cognitive disorders.
Otero-Millan (2020) Fixational Eye Movements in Visual, Cognitive, and Movement Disorders. In: Shaikh A., Ghasia F. (eds) Advances in Translational Neuroscience of Eye Movement Disorders. Contemporary Clinical Neuroscience. Springer, Cham.