The International Space Station (ISS) Ocular Surveillance protocol aims to systematically gather physiological data to characterize the Risk of Microgravity-Induced Visual Impairment and Intracranial Pressure (VIIP) on crewmembers assigned to a six month ISS Increment. The data collected will mirror Medical Requirements Integration Documents (MRID) requirements and testing performed during annual medical exams. The frequency of in-flight and post flight testing will be increased to more accurately assess changes that occur in the visual, vascular, and central nervous systems upon exposure to microgravity and induction of fluid shifting. Monitoring in-flight changes, in addition to post flight recovery, which is the main focus of this protocol.
This investigation hypothesizes that some crewmembers will experience meaningful and detectable changes before, during, and after space flight in at least one or more of the following measurements: visual acuity, intraocular pressure, optic disc edema, choroidal folds, optic nerve sheath distention, optic nerve tortuosity, optic nerve to sheath ratio, globe flattening, and retinal “cotton-wool spots.” Moreover, it is expected that crewmembers will have changes before and after in the Cerebrospinal fluid (CSF) velocity through the aqueduct of Sylvius and the retinal nerve fiber layer. It is further anticipated that measures observed during and after space flight will deviate from the baseline measurements, which may prolonged the recovery period to return to the baseline values.
APPROACH:
The data collected will mirror MRID requirements and testing performed during annual medical exams; however, two additional tests will be performed and the frequency of postflight testing will be increased to more accurately assess changes that occur in the visual, vascular, and central nervous systems.
The preflight MRID required tests are an MRI at launch minus (L-) 21-18 months; Ocular Ultrasound at L- 9-6 months; Vision Testing [Fundoscopy, Intraocular Pressure (IOP/Tonometry), Visual Acuity, Amsler Grid, OCT, Optical Biometry, Refraction, Threshold Visual Fields,]. During Vision Testing, subjects will be administered dilating and numbing agents) at L- 21-18 months and L- 9-6 months. The tests that will be done in addition to MRID requirements are Blood Pressure (BP) at time of IOP (Tonometry) at L- 21-18 months and L- 9-6 months, Vascular Compliance (Cardiac Ultrasound and BP), and TCD at L- 9-6 months.
The postflight MRID required tests are an MRI, Ocular Ultrasound, and Vision Testing at return plus (R+) 1-3 days. In addition to these MRID requirements, BP at time of IOP (Tonometry), Vascular Compliance (Cardiac Ultrasound and BP), and TCD will also be done on R+1-3 days and the entire suite of tests will be done at R+30, R+90, R+180, and R+360 days.
Inflight, the data collected will mirror MRID requirements; however, three additional tests will be performed and the frequency of inflight testing will be increased to more accurately assess changes that occur in the visual, vascular, and central nervous systems. All activities within a Flight Day session may occur within a 5-day window. The inflight MRID required tests are Vision Testing and Vision Questionnaire, Ocular Ultrasound, Fundoscopy, and OCT on flight day (FD) 30, FD 90, and return minus (R-) 30. In addition to these MRID requirements, these tests will also be conducted on FD 10, FD 60, and FD 120. The additional tests, IOP (Tonometry) w/ BP, Vascular Compliance (Cardiac Ultrasound and BP), and TCD, will be conducted on FD 10, FD 30, FD 60, FD 90, FD 120, and R-30.
For extended duration missions, the Inflight operations will increase to FD 10, 30*, 90*, 150*, 210*, 270*, R-30* for all Ocular Health testing, where * indicates data-sharing with existing MRID sessions.
RESULTS: :
This experiment is in progress. Results will be available at a later date.