Some crewmembers on long-duration missions to the International Space Station (ISS) have experienced ophthalmic anatomical changes and visual performance decrements with varying degrees. In these cases, data suggest that intracranial pressure is simultaneously increased. NASA medical operations and research personnel have hypothesized that the microgravity induced cephalad fluid shift may be partially responsible for the observed ophthalmic changes through biomechanical means. Some observed gross physiological responses to spaceflight include an increase in cerebrospinal fluid (CSF) pressure postflight, an apparent increase in interstitial fluid in the head and neck secondary to altered Starling forces and evidenced by facial puffiness and congestion, altered distribution of fluid within the compartments of the head and body, optic nerve sheath distension, posterior globe flattening, choroidal folds, and optic disc edema. NASA has completed some investigations on short duration (~2 weeks) spaceflights to study microgravity induced fluid redistribution and visual acuity changes. Additionally, several experimental and computational studies are currently underway to investigate how fluids are redistributed throughout the body during long-duration missions, and the possible biomechanical pathways causing the observed ophthalmic changes.

However, these works do not quantify the dynamic flow of the CSF and vascular flow throughout the intracranial and ophthalmic region. Moreover, the highly varying clinical findings among the astronaut population suggests that the subject-specific complex anatomical structure of the intracranial compartments and ophthalmic region may be contributing to unique flow dynamics that may cause some astronauts to be more susceptible to Visual Impairment and Intracranial Pressure (VIIP) syndrome than others. Therefore, the objective of this solicitation is to develop computational model(s) that quantify CSF and vascular flow dynamics within the intracranial space and ophthalmic region in microgravity, and identify key conditions (e.g. flow parameters or anatomical structure) that may increase the risk of VIIP syndrome.

Successful proposers must develop and deliver detailed numerical model(s) that quantify how CSF and vascular flow dynamics are altered in microgravity, and the propagative effects on the structure of the eye. The model(s) must also be developed with the capability to interact with other pre-existing numerical models of the cardiovascular system, central nervous system and eye to enable integrative physiology analysis. The model(s) must also be quantitatively verified and validated following the standard of NASA-STD-7009 (https://standards.nasa.gov/documents/detail/3315599) or equivalent. Furthermore, documentation must be provided that clearly captures the modeling approaches used, as well as a model operations/users guide. Finally, the investigation team must also be willing to provide the software source code to NASA to make available as an open source product.

More information regarding VIIP may be found in the 2012 VIIP Evidence Report at http://humanresearchroadmap.nasa.gov/evidence/reports/VIIP.pdf?rnd=0.173595093271507

Required deliverables:

• Develop computational model(s) that quantify cerebrospinal fluid (CSF) and vascular flow dynamics within the intracranial space and ophthalmic region in microgravity, and identify key conditions (e.g. flow parameters or anatomical structure) that may increase the risk of VIIP syndrome.

Please note that a maximum of $750,000 ($250,000/year) for three years is available.

Full details of the above opportunity, among other opportunities, can be found in Appendix A of the NASA Research Announcement (NRA) titled, “Human Exploration Research Opportunities (HERO)” NNJ15ZSA001N.

Appendix A of the HERO NRA and associated documentation can be found at: http://tinyurl.com/2015-Flagship

The HERO NRA including all open appendices is available through the NASA Research Opportunities homepage at: http://tinyurl.com/NASA-HERO-2015.

Appendix A Step-1 proposals are due on September 4, 2015.

Invited Appendix A Step-2 proposals are due on November 23, 2015.