Document Detail

In vivo increase of the human lens equatorial diameter during accommodation.
MedLine Citation:
PMID:  8853390     Owner:  NLM     Status:  MEDLINE    
The movement of the human lens equator during accommodation was examined in vivo. High-resolution ultrasound images of the lens equator were obtained from young human subjects whose amplitude of accommodation was controlled with 1% tropicamide and 2% pilocarpine. To avoid errors that otherwise arise from eye rotation or other movement, the cornea and sclera were used as positional references in comparative studies of the video images obtained from the unaccommodated and accommodated states. During accommodation, the movement at the lens equator involved small displacement; i.e., < 100 microns, and the equator did not move anteriorly or posteriorly but peripherally toward the sclera. These results indicate that the lens equator is under increased zonular tension during accommodation, in contradiction to Helmholtz's widely accepted theory of accommodation.
R A Schachar; C Tello; D P Cudmore; J M Liebmann; T D Black; R Ritch
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of physiology     Volume:  271     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1996 Sep 
Date Detail:
Created Date:  1996-12-05     Completed Date:  1996-12-05     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  R670-6     Citation Subset:  IM    
Department of Physics, University of Texas at Arlington, Dallas 75379, USA.
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MeSH Terms
Accommodation, Ocular / physiology*
Cornea / ultrasonography
Lens, Crystalline / physiology*,  ultrasonography*
Sclera / ultrasonography

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