{{Short description|Pupillary response}} '''Pupillary hippus''', also known as '''pupillary athetosis''', is spasmodic, rhythmic, but regular dilating and contracting [[Pupillary response|pupillary movement]]s between the [[sphincter]] and [[Iris dilator muscle|dilator]] [[Eye muscles|muscles]].<ref name="McLaren">{{cite journal |author1=McLaren J. W. |author2=Erie J. C. |author3=Brubaker R. F. | year = 1992 | title = Computerized analysis of pupillograms in studies of alertness | journal = Investigative Ophthalmology and Visual Science | volume = 33 | pages = 671–6 }}</ref><ref name="Cassin">Cassin, B. and Solomon, S. ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company, 1990.</ref> Pupillary hippus comes from the Greek ''[[wikt:ἵππος#Ancient Greek|hippos]]'' meaning horse, perhaps due to the rhythm of the contractions representing a galloping horse.<ref name="Beatty">Beatty, J., & Lucero-Wagoner, B. (2000). The pupillary system. In J. T. Cacioppo, L. G. Tassinary & G. G. Bernston (Eds.), ''The handbook of psychophysiology'' (2nd ed.) (pp. 142-162). USA: Cambridge University Press.</ref> Notably, ''hippos'' in antiquity referred to involuntary eye movements which are nowadays called [[nystagmus]].<ref>{{Cite journal |last=Gerb |first=Johannes |last2=Brandt |first2=Thomas |last3=Huppert |first3=Doreen |date=July 2023 |title=Historical descriptions of nystagmus and abnormal involuntary eye movements in various ancient cultures |url=http://journals.sagepub.com/doi/10.1177/00368504231191986 |journal=Science Progress |language=en |volume=106 |issue=3 |doi=10.1177/00368504231191986 |issn=0036-8504 |pmc=10469245 |pmid=37642983}}</ref>
It is particularly noticeable when [[pupil]] function is tested with a light,<ref name="Cassin"/> but is independent of eye movements or changes in illumination.<ref name="McLaren"/> It is usually normal, however pathological hippus can occur.<ref name="Cassin"/><ref name="Beatty"/>
Pathologic hippus, the phenomenon of increased oscillation or their amplitude, is associated with [[aconitine|aconite]] poisoning,<ref name="Reddy">Forensic and State Medicine: Reddy</ref> [[altered mental status]], trauma, cirrhosis, and [[renal disease]]; suggesting a common pathway of [[frontal lobe]] dysfunction.<ref name="Denny">{{cite journal |vauthors=Denny JC, Arndt FV, Dupont WD, Neilson EG | year = 2008 | title = Increased hospital mortality in patients with bedside hippus | journal = Am J Med | volume = 121 | issue = 3| pages = 239–45 | pmid = 18328309 | doi=10.1016/j.amjmed.2007.09.014}}</ref> A retrospective study of 117 hospitalized patients with hippus noted an increased 30-day mortality when compared to controls and adjusted for other factors.<ref name="Denny" />
==See also== *[[Athetosis]] *[[Anisocoria]] - condition characterized by an unequal size of the eyes' pupils.
==References== {{Reflist}}
[[Category:Eye]]
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