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A Framework for Modelling Connective Tissue Changes in VIIP SyndromeInsertion of astronauts into microgravity induces a cascade of physiological adaptations, notably including a cephalad fluid shift. Longer-duration flights carry an increased risk of developing Visual Impairment and Intracranial Pressure (VIIP) syndrome, a spectrum of ophthalmic changes including posterior globe flattening, choroidal folds, distension of the optic nerve sheath, kinking of the optic nerve and potentially permanent degradation of visual function. The slow onset of changes in VIIP, their chronic nature, and the similarity of certain clinical features of VIIP to ophthalmic findings in patients with raised intracranial pressure strongly suggest that: (i) biomechanical factors play a role in VIIP, and (ii) connective tissue remodeling must be accounted for if we wish to understand the pathology of VIIP. Our goal is to elucidate the pathophysiology of VIIP and suggest countermeasures based on biomechanical modeling of ocular tissues, suitably informed by experimental data, and followed by validation and verification. We specifically seek to understand the quasi-homeostatic state that evolves over weeks to months in space, during which ocular tissue remodeling occurs. This effort is informed by three bodies of work: (i) modeling of cephalad fluid shifts; (ii) modeling of ophthalmic tissue biomechanics in glaucoma; and (iii) modeling of connective tissue changes in response to biomechanical loading.
Document ID
Acquisition Source
Glenn Research Center
Document Type
Ethier, C. R.
(Georgia Inst. of Tech. Atlanta, GA, United States)
Best, L.
(NASA Glenn Research Center Cleveland, OH United States)
Gleason, R.
(Georgia Inst. of Tech. Atlanta, GA, United States)
Mulugeta, L.
(Universities Space Research Association Houston, TX, United States)
Myers, J. G.
(NASA Glenn Research Center Cleveland, OH United States)
Nelson, E. S.
(NASA Glenn Research Center Cleveland, OH United States)
Samuels, B. C.
(Alabama Univ. Birmingham, AL, United States)
Date Acquired
March 3, 2015
Publication Date
February 12, 2014
Subject Category
Aerospace Medicine
Report/Patent Number
Meeting Information
Meeting: Human Research Program Investigators'' Workshop
Location: Galveston, TX
Country: United States
Start Date: February 12, 2014
End Date: February 13, 2014
Sponsors: Universities Space Research Association, National Space Biomedical Research Inst., NASA Headquarters
Funding Number(s)
WBS: WBS 516724.02.02.10
Distribution Limits
Public Use Permitted.
aerospace medicine
eye (anatomy)
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