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Christian Otto; Fluid shifts in microgravity: The visual impairment and intracranial pressure syndrome in U.S. astronauts. Invest. Ophthalmol. Vis. Sci. 201657(12):.
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© ARVO (1962-2015); The Authors (2016-present)
Presentation Description :
The visual impairment intracranial pressure (VIIP) syndrome is currently NASA’s number one human spaceflight risk. The syndrome, which is related to microgravity exposure, manifests with changes in visual acuity (hyperopic shifts) and in eye structure (optic disc edema, choroidal folds, globe flattening, and distended optic nerve sheaths). In some astronauts, elevated cerebrospinal fluid pressure has been documented following their space mission, reflecting increased intracranial pressure (ICP). While the eye appears to be the main affected organ of this syndrome, the ocular manifestations are thought to be caused by the interaction of several physiologic systems, including the eye, the cardiovascular system, and the central nervous system. The leading hypotheses for the development of VIIP involve microgravity-induced head-ward fluid shifts and CO2 related vasodilation, altered cranial nerve lymphatic drainage of cerebral spinal fluid, along with a loss of gravity-assisted drainage of venous blood from the brain, leading to cephalic venous congestion and increased ICP.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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