Document Detail

A gimbal-mounted pressurization chamber for macroscopic and microscopic assessment of ocular tissues.
MedLine Citation:
PMID:  22010754     Owner:  NLM     Status:  MEDLINE    
The biomechanical model of glaucoma considers intraocular pressure-related stress and resultant strain on load bearing connective tissues of the optic nerve and surrounding peripapillary sclera as one major causative influence that effects cellular, vascular, and axonal components of the optic nerve. By this reasoning, the quantification of variations in the microstructural architecture and macromechanical response of scleral shells in glaucomatous compared to healthy populations provides an insight into any variations that exist between patient populations. While scleral shells have been tested mechanically in planar and pressure-inflation scenarios the link between the macroscopic biomechanical response and the underlying microstructure has not been determined to date. A potential roadblock to determining how the microstructure changes based on pressure is the ability to mount the spherical scleral shells in a method that does not induce unwanted stresses to the samples (for instance, in the flattening of the spherical specimens), and then capturing macroscopic and microscopic changes under pressure. Often what is done is a macroscopic test followed by sample fixation and then imaging to determine microstructural organization. We introduce a novel device and method, which allows spherical samples to be pressurized and macroscopic and microstructural behavior quantified on fully hydrated ocular specimens. The samples are pressurized and a series of markers on the surface of the sclera imaged from several different perspectives and reconstructed between pressure points to allow for mapping of nonhomogenous strain. Pictures are taken from different perspectives through the use of mounting the pressurization scheme in a gimbal that allows for positioning the sample in several different spherical coordinate system configurations. This ability to move the sclera in space about the center of the globe, coupled with an upright multiphoton microscope, allows for collecting collagen, and elastin signal in a rapid automated fashion so the entire globe can be imaged.
Joseph T Keyes; Dongmei Yan; Jacob H Rader; Urs Utzinger; Jonathan P Vande Geest
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of biomechanical engineering     Volume:  133     ISSN:  1528-8951     ISO Abbreviation:  J Biomech Eng     Publication Date:  2011 Sep 
Date Detail:
Created Date:  2011-10-20     Completed Date:  2012-02-15     Revised Date:  2014-09-24    
Medline Journal Info:
Nlm Unique ID:  7909584     Medline TA:  J Biomech Eng     Country:  United States    
Other Details:
Languages:  eng     Pagination:  095001     Citation Subset:  IM    
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MeSH Terms
Biomechanical Phenomena
Extracellular Matrix / metabolism
Eye / cytology*
Intraocular Pressure
Mechanical Processes*
Microscopy / instrumentation*
Sclera / cytology,  physiology
Stress, Mechanical
Grant Support
1S10RR023737-01/RR/NCRR NIH HHS; NEI 1R01EY020890/EY/NEI NIH HHS; R01 EY020890/EY/NEI NIH HHS; R01 EY020890-01A1/EY/NEI NIH HHS; T32 HL007955/HL/NHLBI NIH HHS; T32 HL007955/HL/NHLBI NIH HHS; T32 HL007955-11A1/HL/NHLBI NIH HHS

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