Researchers could be at work soon on new techniques for the detection and treatment of vision problems found in astronauts assigned to long-duration missions aboard the International Space Station (ISS).
A report earlier this month in the journal Radiology, based on magnetic resonance imaging studies on 27 long-duration astronauts, found some with symptoms similar to idiopathic intercranial hypertension, including swelling of the optic nerve and an outward pressure on the eyeballs (Aerospace DAILY, March 15).
The study, whose subjects averaged 108 days in orbit on the ISS or space shuttle, has raised concerns for astronauts assigned to deep-space missions that could require months to years away from gravity.
One study, approved for funding by the National Space Biomedical Research Institute (NSBRI), is scheduled to begin this summer, using an estimated 80 volunteers diagnosed with intracranial hypertension. They will serve as subjects in an effort to evaluate a half-dozen noninvasive techniques for measuring changes in pressure levels that could serve as alternatives to spinal taps, which are considered too risky and difficult to include as a spaceflight assessment, according to Dr. Eric Bershad, an assistant professor of neurology at the Baylor College of Medicine and the principal investigator.
Some of the technologies are based on ultrasound, which has become an increasingly capable diagnostic tool for the evaluation of ISS astronauts, and the Pan Optic Ophthalmoscope, a newer tool for measuring changes to the optic nerve.
“This could have a lot of benefit, not just for trying to figure out what the astronauts are developing, but some of the noninvasive devices could also be used in patients that have brain injuries or other conditions with bleeding around the brain, or stroke, where we need methods of measuring pressure noninvasively,” Bershad said March 19.
Some recent studies also suggest changes in taste and smell experienced by astronauts as they leave gravity could be associated with a shift in fluids from the lower torso into the upper chest and head. That same shift may be associated with a similar increase in pressure around the olfactory nerve, says Dr. Main Zain Urfy, a Baylor critical-care fellow and research participant.
Studies could lead to a range of potential countermeasures, including use of the medication Diamox, which is used to treat idiopathic intercranial hypertension. Other remedies may include the use of the Lower Body Negative Pressure Device, once studied on shuttle missions as a countermeasure to the fainting episodes some astronauts experienced after they landed.
The NSBRI, founded 15 years ago, is funded byat $24 million annually to find solutions to the health risks faced by astronauts and to share new medical techniques and technologies. The work involves more than 60 U.S. research institutions.