A medieval fallacy: the crystalline lens in the center of the eye

Christopher T Leffler,1 Tamer M Hadi,2 Akrithi Udupa,1 Stephen G Schwartz,3 Daniel Schwartz1 1Department of Ophthalmology, Virginia Commonwealth University, Richmond, VA, 2Graduate School of Medicine, University of Tennessee Medical Center, Knoxville, TN, 3Bascom Palmer Eye Institute, University of...

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Autores principales:	Leffler CT, Hadi TM, Udupa A, Schwartz SG, Schwartz D
Formato:	article
Lenguaje:	EN
Publicado:	Dove Medical Press 2016
Materias:	cataract lens history of medicine Ophthalmology RE1-994
Acceso en línea:	https://doaj.org/article/7a3735b76aad4e329615d2f93db1f49f
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spelling	oai:doaj.org-article:7a3735b76aad4e329615d2f93db1f49f2021-12-02T07:35:34ZA medieval fallacy: the crystalline lens in the center of the eye1177-5483https://doaj.org/article/7a3735b76aad4e329615d2f93db1f49f2016-04-01T00:00:00Zhttps://www.dovepress.com/a-medieval-fallacy-the-crystalline-lens-in-the-center-of-the-eye-peer-reviewed-article-OPTHhttps://doaj.org/toc/1177-5483Christopher T Leffler,1 Tamer M Hadi,2 Akrithi Udupa,1 Stephen G Schwartz,3 Daniel Schwartz1 1Department of Ophthalmology, Virginia Commonwealth University, Richmond, VA, 2Graduate School of Medicine, University of Tennessee Medical Center, Knoxville, TN, 3Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA Objective: To determine whether, as most modern historians have written, ancient Greco-Roman authors believed the crystalline lens is positioned in the center of the eye. Background: Historians have written that statements about cataract couching by Celsus, or perhaps Galen of Pergamon, suggested a centrally located lens. Celsus specifically wrote that a couching needle placed intermediate between the corneal limbus and the lateral canthus enters an empty space, presumed to represent the posterior chamber. Methods: Ancient ophthalmic literature was analyzed to understand where these authors believed the crystalline lens was positioned. In order to estimate where Celsus proposed entering the eye during couching, we prospectively measured the distance from the temporal corneal limbus to the lateral canthus in 30 healthy adults. Results: Rufus of Ephesus and Galen wrote that the lens is anterior enough to contact the iris. Galen wrote that the lens equator joins other ocular structures at the corneoscleral junction. In 30 subjects, half the distance from the temporal corneal limbus to the lateral canthus was a mean of 4.5 mm (range: 3.3–5.3 mm). Descriptions of couching by Celsus and others are consistent with pars plana entry of the couching needle. Anterior angulation of the needle would permit contact of the needle with the lens. Conclusion: Ancient descriptions of anatomy and couching do not establish the microanatomic relationships of the ciliary region with any modern degree of accuracy. Nonetheless, ancient authors, such as Galen and Rufus, clearly understood that the lens is located anteriorly. There is little reason to believe that Celsus or other ancient authors held a variant understanding of the anatomy of a healthy eye. The notion of the central location of the lens seems to have arisen with Arabic authors in 9th century Mesopotamia, and lasted for over 7 centuries. Keywords: anatomy, medical history, crystalline lens, cataract couchingLeffler CTHadi TMUdupa ASchwartz SGSchwartz DDove Medical Pressarticlecataractlenshistory of medicineOphthalmologyRE1-994ENClinical Ophthalmology, Vol 2016, Iss Issue 1, Pp 649-662 (2016)
institution	DOAJ
collection	DOAJ
language	EN
topic	cataract lens history of medicine Ophthalmology RE1-994
spellingShingle	cataract lens history of medicine Ophthalmology RE1-994 Leffler CT Hadi TM Udupa A Schwartz SG Schwartz D A medieval fallacy: the crystalline lens in the center of the eye
description	Christopher T Leffler,1 Tamer M Hadi,2 Akrithi Udupa,1 Stephen G Schwartz,3 Daniel Schwartz1 1Department of Ophthalmology, Virginia Commonwealth University, Richmond, VA, 2Graduate School of Medicine, University of Tennessee Medical Center, Knoxville, TN, 3Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA Objective: To determine whether, as most modern historians have written, ancient Greco-Roman authors believed the crystalline lens is positioned in the center of the eye. Background: Historians have written that statements about cataract couching by Celsus, or perhaps Galen of Pergamon, suggested a centrally located lens. Celsus specifically wrote that a couching needle placed intermediate between the corneal limbus and the lateral canthus enters an empty space, presumed to represent the posterior chamber. Methods: Ancient ophthalmic literature was analyzed to understand where these authors believed the crystalline lens was positioned. In order to estimate where Celsus proposed entering the eye during couching, we prospectively measured the distance from the temporal corneal limbus to the lateral canthus in 30 healthy adults. Results: Rufus of Ephesus and Galen wrote that the lens is anterior enough to contact the iris. Galen wrote that the lens equator joins other ocular structures at the corneoscleral junction. In 30 subjects, half the distance from the temporal corneal limbus to the lateral canthus was a mean of 4.5 mm (range: 3.3–5.3 mm). Descriptions of couching by Celsus and others are consistent with pars plana entry of the couching needle. Anterior angulation of the needle would permit contact of the needle with the lens. Conclusion: Ancient descriptions of anatomy and couching do not establish the microanatomic relationships of the ciliary region with any modern degree of accuracy. Nonetheless, ancient authors, such as Galen and Rufus, clearly understood that the lens is located anteriorly. There is little reason to believe that Celsus or other ancient authors held a variant understanding of the anatomy of a healthy eye. The notion of the central location of the lens seems to have arisen with Arabic authors in 9th century Mesopotamia, and lasted for over 7 centuries. Keywords: anatomy, medical history, crystalline lens, cataract couching
format	article
author	Leffler CT Hadi TM Udupa A Schwartz SG Schwartz D
author_facet	Leffler CT Hadi TM Udupa A Schwartz SG Schwartz D
author_sort	Leffler CT
title	A medieval fallacy: the crystalline lens in the center of the eye
title_short	A medieval fallacy: the crystalline lens in the center of the eye
title_full	A medieval fallacy: the crystalline lens in the center of the eye
title_fullStr	A medieval fallacy: the crystalline lens in the center of the eye
title_full_unstemmed	A medieval fallacy: the crystalline lens in the center of the eye
title_sort	medieval fallacy: the crystalline lens in the center of the eye
publisher	Dove Medical Press
publishDate	2016
url	https://doaj.org/article/7a3735b76aad4e329615d2f93db1f49f
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A medieval fallacy: the crystalline lens in the center of the eye

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