Hippus
Pupillary hippus, also known as pupillary athetosis, is spasmodic, rhythmic, but regular dilating and contracting pupillary movements between the sphincter and dilator muscles.[1][2] Pupillary hippus comes from the Greek hippos meaning horse, perhaps due to the rhythm of the contractions representing a galloping horse.[3] Notably, hippos in antiquity referred to involuntary eye movements which are nowadays called nystagmus.[4]
It is particularly noticeable when pupil function is tested with a light,[2] but is independent of eye movements or changes in illumination.[1] It is usually normal, however pathological hippus can occur.[2][3]
Pathologic hippus, the phenomenon of increased oscillation or their amplitude, is associated with aconite poisoning,[5] altered mental status, trauma, cirrhosis, and renal disease; suggesting a common pathway of frontal lobe dysfunction.[6] A retrospective study of 117 hospitalized patients with hippus noted an increased 30-day mortality when compared to controls and adjusted for other factors.[6]
See also
[edit | edit source]- Athetosis
- Anisocoria - condition characterized by an unequal size of the eyes' pupils.
References
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- ^ a b c Cassin, B. and Solomon, S. Dictionary of Eye Terminology. Gainesville, Florida: Triad Publishing Company, 1990.
- ^ a b 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.
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Forensic and State Medicine: Reddy
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
