Book chapter
25 - Regulation of Light Through the Pupil
Adler's Physiology of the Eye, pp.527-548
Elsevier, Twelfth Edition
2025
DOI: 10.1016/B978-0-323-83406-3.00025-8
Abstract
The pupil serves to constantly regulate the amount of light entering the eye to maintain consistent retinal illumination. This chapter reviews the anatomy of the pupil light response with attention to the clinical import of the afferent and efferent arms of this reflex. The relative afferent pupillary defect is present when one eye supplies relatively less afferent innervation than the other, as in unilateral optic neuropathies. Clinical and computerized assessments of this important phenomenon are described. Anisocoria refers to inequality in the pupil diameter, which can occur because of asymmetric sympathetic or parasympathetic innervation, muscular injury, pharmacologic effect, or it can be normal. Horner’s syndrome is an important cause of anisocoria that is greater in darkness, while third nerve palsy, tonic pupils, and iris sphincter trauma cause anisocoria greater in light. Understanding of the anatomy and physiology allows the clinician to glean a wealth of diagnostic information from the pupil exam.
Details
- Title: Subtitle
- 25 - Regulation of Light Through the Pupil
- Creators
- Randy H. KardonEdward Linton
- Resource Type
- Book chapter
- Publication Details
- Adler's Physiology of the Eye, pp.527-548
- Edition
- Twelfth Edition
- DOI
- 10.1016/B978-0-323-83406-3.00025-8
- Publisher
- Elsevier; Philadelphia, PA
- Language
- English
- Date published
- 2025
- Academic Unit
- Iowa Neuroscience Institute; Ophthalmology and Visual Sciences
- Record Identifier
- 9984949519002771
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