Prospective Observational Study of Ocular Health in ISS Crews (Ocular Health) – 11.22.16
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Science Objectives for Everyone
Crew members’ bodies change in a variety of ways during space flight, and some experience impaired vision. The Prospective Observational Study of Ocular Health in ISS Crews (Ocular Health) protocol gathers data on crew members’ visual health during and after long-duration space station missions. Tests monitor microgravity-induced visual impairment, as well as changes believed to arise from elevated intracranial pressure, to characterize how living in microgravity can affect the visual, vascular and central nervous systems. The investigation also measures how long it takes for crew members to return to normal after they return to Earth.
Science Results for Everyone
Christian Otto, Universities Space Research Association (USRA), Houston, TX, United States
C Robert Gibson, O.D., Coastal Eye Associates, Webster, TX, United States
Ashot E. Sargsyan, M.D., KBRwyle, Houston, TX, United States
Robert J. Ploutz-Snyder, Ph.D., University of Michigan School of Nursing, Ann Arbor, MI, United States
David Alexander, M.D., Johnson Space Center, Houston, TX, United States
Roy Riascos-Castaneda, M.D., University of Texas Medical Branch, Houston, TX, United States
Nimesh Patel, O.D., Ph.D., University of Houston, Houston, TX, United States
Brian Samuels, M.D., Ph.D., EyeSight Foundation of Alabama Vision Research Laboratories, Birmingham, AL, United States
Robert Hamilton, Neural Analytics, Inc., Los Angeles, CA, United States
NASA Johnson Space Center, Human Research Program, Houston, TX, United States
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
NASA Research Office – Human Research Program (NASA Research-HRP)
Earth Benefits, Scientific Discovery, Space Exploration
ISS Expedition Duration
March 2013 – March 2016; March 2016 – September 2016
Experiment DescriptionResearch Overview
The purpose of this study is to collect evidence to characterize the risk and define the visual changes, vascular changes, and central nervous system (CNS) changes, including intracranial pressure, observed during long-duration exposure to microgravity, including postflight time course for recovery to baseline. This study gathers information that can be used to assess the risk of Microgravity-Induced Visual Impairment/Intracranial Pressure (VIIP) and guide future research needs.
1. It is expected that some crew members may experience meaningful and detectable in-flight changes in at least one or more of the following: clarity of vision (visual acuity), pressure inside the eyeball (intraocular pressure), swelling of the optic disc (optic disc edema or papilledema), folds in the vascular layer of the eye (choroidal folds), optic nerve sheath distention, elongation of the optic nerve resulting from an increase in cerebrospinal fluid or CSF (optic nerve tortuosity), optic nerve-to-sheath ratio, flattening of the back part of the eye (globe flattening), and retinal “cotton-wool spots” (retinal nerve cells damaged by lack of blood flow), cardiovascular and cerebrovascular compliance and intracranial pressure.
2. It is expected that some crew members may experience meaningful pre- to postflight changes in one or more of the following: visual acuity, intraocular pressure, optic disc edema (papilledema), retinal nerve fiber layer, choroidal folds, optic nerve sheath distention, optic nerve tortuosity, globe flattening, retinal “cotton-wool spots”, smaller changes in blood volume relative to increases in blood pressure (vascular compliance), intracranial pressure, increased CSF production, signs of elevated CSF pressure (pituitary concavity), and areas of constriction within veins of the brain.
3. It is expected that if an in-flight or postflight measure deviates from preflight baseline measures, the time required to recover to baseline (preflight values) increases with the severity of the deviation.
Results from Ocular Health address several gaps in current knowledge, including physical and functional changes in the eyes during and after spaceflight. Systematic measurements of the visual, vascular, and central nervous system can inform future research, and develop countermeasures to safeguard crew members’ vision. In addition, results can demonstrate the potential risk for crews on long-duration space missions. If microgravity is entirely or partially responsible for changes to the visual system, crews operating on missions five times longer than current space station expeditions may be negatively impacted.
Ocular Health provides insight into structural changes that can occur in the eyes and nervous system, which could be relevant for patients suffering from a wide range of ocular diseases, such as glaucoma. It also provides data that could be used to help patients suffering from brain diseases, such as hydrocephalus and high blood pressure in the brain.
OperationsOperational Requirements and Protocols
A total of 12 subjects are required for this investigation. In-flight sessions are planned at FD10, FD30, FD60, FD90, FD120, and R-30 for a mission duration of six months and FD10, 30, 90, 150, 210, 270, and R-30 for a mission duration of one year. Tolerance for each test session is +7 days, with at least 14 days between the last test of one FD session and the first test of the next FD session. All activities associated with the session required on a given FD may occur within a 5 day window. Both an operator and a subject are required for the ultrasound scans, fundoscopy, tonometry, OCT, and blood pressure, along with real-time video downlink to enable remote guidance by ground experts.
Ground Based Results Publications
Kramer LA, Hasan KM, Sargsyan AE, Wolinsky JS, Hamilton DR, Riascos-Castaneda R, Carson WK, Heimbigner J, Patel VS, Romo S, Otto C. Mr-derived cerebral spinal fluid hydrodynamics as a marker and a risk factor for intracranial hypertension in astronauts exposed to microgravity. Journal of Magnetic Resonance Imaging. 2015; eoub. DOI: 10.1002/jmri.24923. PMID: 25920095.
Marshall-Bowman K, Barratt MR, Gibson CR. Ophthalmic Changes and Increased Intracranial Pressure Associated with Long Duration Spaceflight: An Emerging Understanding. Acta Astronautica. 2013 June-July; 87: 77-87. DOI: 10.1016/j.actaastro.2013.01.014.
Otto C, Barr YR, Platts SH, Ploutz-Snyder RJ, Sargsyan AE, Alexander D, Riascos-Castaneda R, Gibson CR, Patel N. Prospective observational study of ocular health in ISS crews-The Ocular Health Study. 2015 NASA Human Research Program Investigator’s Workshop, Galveston TX ; 2015 January 13 1 pp.
Michael AP, Marshall-Bowman K. Spaceflight-induced intracranial hypertension. Aerospace Medicine and Human Performance. 2015 June; 86(6): 557-562. DOI: 10.3357/AMHP.4284.2015.
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NASA Image: ISS036E006522 – Astronaut Karen Nyberg performs an Ocular Health (OH) Fundoscope Exam.
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NASA Image: ISS037E006560 – NASA astronaut Michael Hopkins Eflight engineer, performs ultrasound eye imaging in the Columbus laboratory of the International Space Station.
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NASA Image: ISS044E033346 – View of NASA astronaut Scott Kelly with JAXA Kimiya Yui during Fundoscopy Exam.
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