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] .

Sep 23, 2018 · Pupillary hippus (PH) refers to spontaneous bilateral synchronous rhythmic constriction and dilatation of the pupils [1]. This rare phenomenon is spasmodic, cyclic and bilaterally in phase, and is usually considered benign [2].

The semantic expression ‘pupillary nystagmus’ is intended only as a current, but suggestive, variant with the aim of referring to the common traits that the phenomenon of pupillary hippus has with extravestibular nystagmus.

When light reaches a pupil there should be a normal direct and consensual response. An RAPD is diagnosed by observing paradoxical dilatation when light is directly shone in the affected pupil after being shown in the healthy pupild to be from a pathologic process.

Dec 14, 2021 · It mainly caused by incomplete optic nerve lesion or very severe retinal disease. Hippus: Basically it is the alternative rhythmic dilatation and constriction of the pupil and this oscillation are very large and sometimes often independent of the light.

Oct 10, 2019 · Hippus is the normal rhythmic pupillary oscillation commonly seen when light stimulates either eye. Both pupils oscillate in synchrony, and the amplitude and frequency vary ( Table 12.2). Changes in the pupil innervation will produce dilation or constriction of the pupil.

What is Hippus? Rhythmic constriction and dilation of the pupil. Can be easily observed when light is shined on eyes Hippus is however independent of light Often likened to a person dancing or a horse galloping Rhythmic Physiological or Pathological: Physiological but can be both

Normal Pupillary Reaction, with Hippus: In this case, there is no RAPD, as each pupil constricts equally with no redilation after the light is switched from pupil to pupil. Hippus is present, which is a normal fluctuation in pupillary size under steady illumination.

In this study we aimed to determine the roles of the SNS and PNS in pupillary hippus by pharmacologic means. Participants received either a PNS antagonist (tropicamide) or a SNS agonist (phenylephrine) to dilate their pupil.

Jan 1, 2017 · Pupillary hippus can be extinguished by antagonizing the PNS, whereas agonizing the SNS dilates the pupil without affecting hippus. This suggests that hippus originates from central PNS activity, and not from SNS activity, or oscillations in the balance between PNS and SNS at the pupil.