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[[Image:Eye dilate.gif|thumb|250ppx|right|Pupillary response]]
[[Image:Eye dilate.gif|thumb|250ppx|right|Pupillary response]]
'''Pupillary response''' is a physiological response that varies the size of the [[pupil]] via the optic and oculomotor cranial nerve, resulting in either the constriction ([[miosis]])<ref>{{cite journal |author=Ellis CJ |title=The pupillary light reflex in normal subjects |journal=Br J Ophthalmol |volume=65 |issue=11 |pages=754–9 |date=November 1981 |pmid=7326222 |pmc=1039657 |doi= 10.1136/bjo.65.11.754|url=http://bjo.bmj.com/content/65/11/754.full.pdf}}</ref> or dilation ([[mydriasis]], expansion), via relaxation or contraction of the [[iris dilator muscle]]. The response can have a variety of causes, from an [[pupillary reflex|involuntary reflex reaction]] to exposure or inexposure to light — in low light conditions a dilated pupil lets more light into the eye — or it may indicate interest in the subject of attention or indicate [[sexual arousal|sexual stimulation]].<ref>{{Citation
'''Pupillary response''' is a physiological response that varies the size of the [[pupil]] via the optic and oculomotor cranial nerve, resulting in either the constriction ([[miosis]])<ref>{{cite journal |author=Ellis CJ |title=The pupillary light reflex in normal subjects |journal=Br J Ophthalmol |volume=65 |issue=11 |pages=754–9 |date=November 1981 |pmid=7326222 |pmc=1039657 |doi= 10.1136/bjo.65.11.754|url=http://bjo.bmj.com/content/65/11/754.full.pdf}}</ref> or dilation ([[mydriasis]], expansion) through relaxation or contraction of the [[iris dilator muscle]]. The response can have a variety of causes, from an [[pupillary reflex|involuntary reflex reaction]] to exposure or inexposure to light — in low light conditions a dilated pupil lets more light into the eye — or it may indicate interest in the subject of attention or indicate [[sexual arousal|sexual stimulation]].<ref>{{Citation
| last1 = Hess | first1 = Eckhard H.
| last1 = Hess | first1 = Eckhard H.
| author1-link = Eckhard Hess
| author1-link = Eckhard Hess
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[[Anisocoria]] is the condition of one pupil being more dilated than the other.
[[Anisocoria]] is the condition of one pupil being more dilated than the other.

Pupillary dilation pathway is mediated by the sympathetic division of the autonomic nervous system. Interruption at any level leads to Horner's syndrome (miosis, anhydrosis, ptosis). Hypothalamic neurons of the paraventricular nucleus project directly to the ciliospinal center (T1-T2) of the intermediolateral cell column of the spinal cord, which projects preganglionic sympathetic fibers through the sympathetic trunk to the superior cervical ganglion, which projects postganglionic sympathetic fibers through the perivascular plexus of the carotid system to the dilator muscle of the iris.


[[File:Horner's Syndrome and Autonomic innervation of the eye.svg|thumb|350px|right|Scheme showing sympathetic and parasympathetic innervation of the pupil and sites of lesion in a Horner's syndrome.]]
[[File:Horner's Syndrome and Autonomic innervation of the eye.svg|thumb|350px|right|Scheme showing sympathetic and parasympathetic innervation of the pupil and sites of lesion in a Horner's syndrome.]]

Revision as of 09:05, 24 February 2014

Pupillary response

Pupillary response is a physiological response that varies the size of the pupil via the optic and oculomotor cranial nerve, resulting in either the constriction (miosis)[1] or dilation (mydriasis, expansion) through relaxation or contraction of the iris dilator muscle. The response can have a variety of causes, from an involuntary reflex reaction to exposure or inexposure to light — in low light conditions a dilated pupil lets more light into the eye — or it may indicate interest in the subject of attention or indicate sexual stimulation.[2] The pupils contract immediately before someone falls asleep.[3] A pupillary response can be intentionally conditioned as a Pavlovian response to some stimuli.[4]

The latency of pupillary response (the time in which it takes to occur) increases with age.[5] Use of central nervous system stimulant drugs and some hallucinogenic drugs can cause dilation of the pupil.[6]

In ophthalmology, intensive studies of pupillary response are conducted via videopupillometry.[7]

Anisocoria is the condition of one pupil being more dilated than the other.

Pupillary dilation pathway is mediated by the sympathetic division of the autonomic nervous system. Interruption at any level leads to Horner's syndrome (miosis, anhydrosis, ptosis). Hypothalamic neurons of the paraventricular nucleus project directly to the ciliospinal center (T1-T2) of the intermediolateral cell column of the spinal cord, which projects preganglionic sympathetic fibers through the sympathetic trunk to the superior cervical ganglion, which projects postganglionic sympathetic fibers through the perivascular plexus of the carotid system to the dilator muscle of the iris.

Scheme showing sympathetic and parasympathetic innervation of the pupil and sites of lesion in a Horner's syndrome.
Sympathetic connections of the ciliary and superior cervical ganglia.
Pupillary responses
Constriction Dilation
Muscular mechanism Relaxation of iris dilator muscle Activation of iris dilator muscle
Cause in pupillary light reflex Increased light Decreased light
Other physiological causes Fight-or-flight response
Corresponding non-physiological state Miosis Mydriasis

See also

References

  1. ^ Ellis CJ (November 1981). "The pupillary light reflex in normal subjects" (PDF). Br J Ophthalmol. 65 (11): 754–9. doi:10.1136/bjo.65.11.754. PMC 1039657. PMID 7326222.
  2. ^ Hess, Eckhard H.; Polt, James M. (5 August 1960), "Pupil Size as Related to Interest Value of Visual Stimuli", Science, 132 (3423): 349–50, doi:10.1126/science.132.3423.349, PMID 14401489 {{citation}}: Check date values in: |date= (help)CS1 maint: date and year (link)
  3. ^ Lowenstein, Otto; Feinberg, Richard; Loewenfeld, Irene E. (April 1963), "Pupillary Movements During Acute and Chronic Fatigue: A New Test for the Objective Evaluation of Tiredness" (PDF), Investigative Ophthalmology, 2 (2), St. Louis: C.V. Mosby Company: 138–157 {{citation}}: Check date values in: |date= (help)CS1 maint: date and year (link)
  4. ^ Baker, Lynn Erland (1938). "The Pupillary Response Conditioned to Subliminal Auditory Stimuli". Ohio State University. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)CS1 maint: date and year (link)
  5. ^ Podolak, Edward; Feinberg, Richard (September 1965), Latency of pupillary reflex to light stimulation and its relationship to aging ([dead link‍]), Federal Aviation Agency, Office of Aviation Medicine, Georgetown Clinical Research Institute, p. 12, OCLC 84657376 {{citation}}: Check date values in: |date= (help)CS1 maint: date and year (link)
  6. ^ Jaanus SD (1992), "Ocular side effects of selected systemic drugs", Optom Clin, 2 (4): 73–96, PMID 1363080
  7. ^ Ishikawa, S.; Naito, M.; Inaba, K. (1970), "A new videopupillography", Ophthalmologica, 160 (4): 248–259, doi:10.1159/000305996, PMID 5439164 {{citation}}: Check date values in: |date= (help)CS1 maint: date and year (link)


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