NASA Grant Funds Research into Visual Changes during Long Space Flights
Noam Alperin, Ph.D., professor of radiology and biomedical engineering, and Director of the Physiologic Imaging and Modeling Lab, has been awarded a $600,000 grant from the National Aeronautics and Space Administration (NASA) to study a condition causing blurred vision that occurs in many astronauts who spend long periods in space.
The condition, known as vision impairment and intracranial pressure syndrome, or VIIP, occurs in about two-thirds of astronauts who have been deployed on the International Space Station for six months or longer. The most consistent signs associated with VIIP are ophthalmic anatomical changes, including flattening of the posterior sclera, known as globe flattening, and protrusion of the optic disk, or nerve protrusion. The longer an astronaut remains in space, the worse the deformation becomes.
VIIP generally resolves itself following return to earth – but not always, and for a few astronauts the ophthalmic changes have been permanent. As NASA plans continued long-term deployments aboard the space station, and eventual lengthy voyages such as manned flights to Mars, there is a strong interest in learning how VIIP might be prevented or minimized.
Alperin’s research will attempt to improve understanding of VIIP by trying to create it in earthbound human test subjects. In fact, he has conducted research on a similar condition – known as idiopathic intracranial hypertension (IIH) – which primarily affects overweight women of child-bearing age.
Several years ago, Alperin and Byron L. Lam, M.D., professor of ophthalmology and the Robert Z. and Nancy J. Greene Chair in Ophthalmology at Bascom Palmer Eye Institute, developed a novel MRI procedure to study IIH.
“Our collaboration is a textbook example of how two different disciplines can get together and make an impact on a field they both study,” said Alperin.
Their work attracted NASA’s attention in 2010, after the agency began seeing similar changes in returning astronauts. Alperin studied astronauts before and after space shuttle flights – comparatively short-term missions that became the control sample for additional studies involving astronauts returning from extended ISS deployments. In all, more than 20 NASA astronauts were studied.
“At first NASA believed VIIP was a type of cardiovascular issue, but our work demonstrates that the cerebrospinal fluid system is clearly involved in the formation of VIIP,” said Alperin.
Under the new grant, Alperin will study approximately 10 subjects who will remain in bed, lying on their backs with their heads tilted down, for a period of 30 days. It is believed that this will result in a headward shift of cerebrospinal fluid, producing a VIIP condition similar to that experienced by the astronauts. Data gathered from the MRI procedure developed by Alperin, as well as from another procedure called optical coherence tomography, will be used to monitor changes in globe flattening, optic nerve protrusion and retinal nerve fiber layer thickness.
In addition, study subjects will be breathing air with a higher percentage of CO2 than that on earth, replicating the air typically breathed by astronauts in space. This is expected to help determine whether VIIP is also linked to space-induced cognitive slowing, or “space fog,” which impairs astronauts’ performance in space.
The bed rest study, which will begin in the fall, will be conducted at a new research facility constructed by NASA and DLR, the German space agency, in Cologne, Germany.