Walsh & Hoyt: The Pupil Light and Near Reflexes and Their Relationship to the Autonomic Nervous System

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Identifier wh_ch14_p660
Title Walsh & Hoyt: The Pupil Light and Near Reflexes and Their Relationship to the Autonomic Nervous System
Creator Randy H. Kardon, MD, PhD
Affiliation Director of Neuro-Ophthalmology Services, Ophthalmology and Visual Sciences, University of Iowa
Subject Autonomic Nervous System; Anatomy; Physiology; Pupil Light Reflexes; Near Reflexes; Autonomic Nervous System Relationship
Description The major function of the pupil is to aid in optimizing retinal illumination to maximize visual perception. In dim light, dilation of the pupil provides an immediate means for maximizing the number of photons reaching the retina, which supplements the dark-adaptive mechanisms of retinal-gain control. Under bright light, pupil constriction can reduce retinal illumination by up to 1.5 log units. Although this reduction in retinal illumination is only a portion of the 12-log unit range of light sensitivity of the retina, it provides an important and immediate contribution to early light adaptation. Patients with a fixed immobile pupil are usually very symptomatic under conditions of changing illumination, emphasizing the important role of the pupil in optimizing visual perception over a wide range of lighting conditions of the environment.
Date 2005
Language eng
Format application/pdf
Type Text
Source Walsh and Hoyt's Clinical Neuro-Ophthalmology, 6th Edition
Relation is Part of Walsh and Hoyt's Clinical Neuro-Ophthalmology Walsh and Hoyt's Clinical Neuro-Ophthalmology
Collection Neuro-ophthalmology Virtual Education Library: NOVEL http://NOVEL.utah.edu
Publisher Wolters Kluwer Health, Philadelphia
Holding Institution Spencer S. Eccles Health Sciences Library, University of Utah, 10 N 1900 E SLC, UT 84112-5890
Rights Management Copyright 2005. For further information regarding the rights to this collection, please visit: https://NOVEL.utah.edu/about/copyright
ARK ark:/87278/s6pk3qk1
Setname ehsl_novel_whts
ID 185661
Reference URL https://collections.lib.utah.edu/ark:/87278/s6pk3qk1
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