Introduction: Saccades are rapid, yoked eye movements in an effort to direct a target over fovea. The complex circuitry of saccadic eye movements has been exhaustively described. As a result clinicians can elegantly localize the pathology if it falls on the neuraxis responsible for saccades. Traditionally saccades are studied with their quantitative characteristics such as amplitude, velocity, duration, direction, latency and accuracy.
Areas covered: Amongst all subtypes, the physiology of the visually guided saccades is most extensively studied. Here we will review the basic and pertinent neuro-anatomy and physiology of visually guided saccade and then discuss common or classic disorders affecting the velocity of visually guided saccades. We will then discuss the basic mechanism for saccade slowing in these disorders.
Expert commentary: Prompt appreciation of disorders of saccade velocity is critical to reach appropriate diagnosis. Disorders of midbrain, cerebellum, or basal ganglia can lead to prolonged transition time during gaze shift and decreased saccade velocity.
Keywords: eye movements; saccade; saccade velocity.
Conflict of interest statement
Declaration of interest The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
Vestibuloocular reflex inhibition and gaze saccade control characteristics during eye-head orientation in humans.J Neurophysiol. 1988 Mar;59(3):997-1013. doi: 10.1152/jn.19126.96.36.1997. J Neurophysiol. 1988. PMID: 3367207
Blinks slow memory-guided saccades.J Neurophysiol. 2013 Feb;109(3):734-41. doi: 10.1152/jn.00746.2012. Epub 2012 Nov 14. J Neurophysiol. 2013. PMID: 23155174 Free PMC article.
Central mesencephalic reticular formation (cMRF) neurons discharging before and during eye movements.J Neurophysiol. 1996 Apr;75(4):1546-72. doi: 10.1152/jn.19188.8.131.526. J Neurophysiol. 1996. PMID: 8727396
Slow saccades in cerebellar disease.Cerebellum Ataxias. 2019 Jan 17;6:1. doi: 10.1186/s40673-018-0095-9. eCollection 2019. Cerebellum Ataxias. 2019. PMID: 30680221 Free PMC article. Review.
The diagnostic value of saccades in movement disorder patients: a practical guide and review.J Clin Mov Disord. 2015 Oct 15;2:14. doi: 10.1186/s40734-015-0025-4. eCollection 2015. J Clin Mov Disord. 2015. PMID: 26788350 Free PMC article. Review.