saccadic velocity
Saccadic velocity is the angular speed of a saccade, which ranges from 30 to 700 degrees per second.1 Speed rises with the amplitude of the movement, so larger saccades are faster.1,2 The consistent relationship among saccadic duration, peak velocity and amplitude is called the main sequence.2
Measuring saccadic velocity helps distinguish a paretic limitation of eye movement from a mechanical one.3 With a paralyzed muscle, velocity into its field of action is markedly decreased, and a slow, drifting movement replaces the normal rapid saccade.3,4 With a mechanical restriction, velocity into the field of apparent paresis stays normal, and the movement halts suddenly.3,4
Electro-oculography can record these eye movements, but it is only an auxiliary method in evaluating a paralytic condition of the extraocular muscles.3 Saccadic velocity can be used alongside the forced duction test or a measure of generated muscle force to assess the function of a paralyzed muscle.3
More detail
Saccades accelerate sharply early in the movement, reach peak velocity and then decelerate more gradually. For a 60° saccade, the eye took 49 ms to reach peak velocity and 93 ms to complete the movement; the time to peak velocity was relatively independent of amplitude.1 Deviations from the main sequence can be used to identify abnormalities in the oculomotor pathways.2
Sources (9)
- von Noorden and Campos, Binocular Vision and Ocular Motility, ch. 4
- Adler's Physiology of the Eye, ch. 8
- von Noorden and Campos, Binocular Vision and Ocular Motility, ch. 20
- Kanski, Clinical Ophthalmology (2024), ch. 4
- Boghen, D., Troost, B.T., Daroff, R.B., Dell'Osso, L.F. and Birkett, J.E. 1974. Velocity characteristics of normal human saccades. Investigative Ophthalmology & Visual Science, 13(8), pp.619-623.
- Leigh, R.J. and Zee, D.S. 2015. The neurology of eye movements. 5th ed. New York: Oxford University Press.
- Rutstein, R. and Daum, K. 1997. Anomalies of Binocular Vision: Diagnosis & Management. St. Louis: Mosby.
- Rucker, J.C. 2005. Normal and abnormal saccadic eye movements. Neurologic Clinics, 23(4), pp.1123-1147.
- Yee, R.D., Baloh, R.W. and Honrubia, V. 1980. Study of congenital nystagmus waveforms in upright and supine positions. Investigative Ophthalmology & Visual Science, 19(5), pp.544-552.
Reviewed October 2026