Polaris Program enlists professors to study vision changes in astronauts

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Astronauts aboard the SpaceZ Polaris Dawn multi-day high-altitude mission will conduct health impact research to gain a better understanding of the impact of spaceflight-associated neuro-ocular syndrome (SANS) on humans who travel into space.

The multi-day mission launched on September 10 with equipment belonging to Prem Subramanian, MD, PhD, chief of neuro-ophthalmology at the University of Colorado of Medicine.

According to a CU news release, Subramanian and Allie Hayman, PhD, a CU Boulder aerospace engineering assistant professor, sent with the astronauts specialized optical equipment to gather data from astronauts’ eyes and will analyze the results during and after the 5-day mission.¹

“This project is an amazing collaboration with astronauts forging the way for deep space exploration,” Subramanian said in the news release. “It’s the first time we can get dynamic information on how the body reacts to the transition to spaceflight.”

The Polaris Dawn crew aboard the SpaceX Dragon spacecraft includes Jared Isaacman, mission commander; Scott Poteet, mission pilot; Sarah Gillis, mission specialist; and Anna Menon, mission specialist and medical officer. Polaris Dawn is the first of 3 human spaceflights under the SpaceX Polaris program.²

The crew was to use its nearly 5 days in orbit to perform some 40 experiments, while also raising funds for St. Jude Children’s Research Hospital.

The Polaris Dawn crew underwent more than 2 years of training in preparation for the mission, including centrifuge operations, hundreds of hours of Dragon simulations, skydiving, survival training, high performance aircraft piloting, Zero-G flight training and altitude training, as well as classroom academics and medical testing. The crew also received EVA training, both underwater and suspended operations, as well as the associated medical training.³

Since 1998, astronauts sent to the International Space Station have been provided with “space anticipation glasses” by NASA. These glasses have adjustable refraction settings to meet changing vision needs, similar to binoculars. In 2011, NASA began conducting MRI scans on astronauts following missions, which revealed potentially increased pressure in their brains as well as papilledema in more than half of the astronauts.¹

Subramanian said in the news release that researchers are trying to determine what causes these changes to the eyes of space travelers.

“We’ve backed off from the idea that it’s necessarily caused by elevated pressure in the head,” he said. “One of the theories is that it may be a balance between intraocular pressure and intracranial pressure, or even pressure in the blood vessels that alters fluid dynamics in the eye socket, or orbit. All of those things are probably interacting to cause this problem.”

For the Polaris Dawn mission, Subramanian sent SENSIMED Triggerfish lenses, which are “smart” contact lenses. They track eye pressure fluctuation and changes in cornea dimensions in glaucoma patients.¹

Kaweh Mansouri, MD, a member of, the University of Colorado Department of Ophthalmology, was involved in the development of the lenses, which will monitor astronauts’ eyes during launch and as they transition to microgravity, a condition of apparent weightlessness. The lenses contain sensors that transmit data to an antenna and local storage device, enabling Subramanian to collect and analyze data upon their return.¹

Another part of equipment sent up by the team is the QuickSee, which will measure astronauts’ refractive error.

“We're looking for changes in the axial length of the eye, because we know that the eye gets a little shorter when you go into space,” Subramanian explained in the news release. “We're trying to get more concrete data on which layers of the eye are changing because that helps us understand what could be driving the optic nerve swelling.”

University of Colorado of Medicine professors sent Triggerfish “smart” contact lenses to monitor changes to astronauts’ eyes during the SpaceX Polaris Dawn mission. (Image credit: John Krais/Polaris program)

Subramanian has been involved with the U.S. space program for more then a decade, following his 2013 lecture at a NASA meeting on papilledema. In 2014, he was named to the National Academy of Medicine’s Committee on Aerospace Medicine and the Medicine of Extreme Environments, a position he continues to hold.¹

As an engineer, Hayman has developed techniques to monitor intracranial pressure non-invasively by measuring signals from the inner ear. She also has worked with Subramanian to study the use of artificial gravity – with a short radius centrifuge – as a way to treat or prevent SANS.

Subramanian pointed out in the news release that the terrestrial version of this disease – idiopathic intracranial hypertension, or IIH – falls squarely into neuro-ophthalmology.

“Like SANS, IIH leads to optic nerve swelling, and it can result in permanent vision loss,” he said in the news release. “That’s why the research will not only help prepare for future space exploration, but also provide insight into eye conditions that occur on Earth.”

Moreover, Subramanian said in the CU news release that he believes research into SANS could help ophthalmologists understand the biology of the eye and orbit, how variations in blood flow affect the eyes and vision, and help them learn why people on Earth get elevated intracranial pressure.

Subramanian also pointed out that solving the issue ultimately can hep advance deep space exploration, which he said is considered by NASA to be the second leading hazard behind radiation exposure that will need countermeasures before humans can pursue long-duration spaceflight.¹

“It’s gratifying to be able to participate in research like this,” Subramanian concluded in the news release. “It is an acknowledgment of the longstanding expertise we have at the University of Colorado, in ophthalmology as well as aerospace medicine. And it’s a recognition of the strength of collaboration between the institutions that make up CU.”

References:

1. Lapp T. Polaris Program Enlists CU Professors to Study Vision Changes in Astronauts. Cuanschutz.edu. Published September 10, 2024. Accessed September 11, 2024. https://news.cuanschutz.edu/ophthalmology/spacex-enlists-cu-professors-to-study-vision-changes-in-astronauts

2. Team - Polaris Program. Polaris Program. Published October 20, 2022. Accessed September 11, 2024. https://polarisprogram.com/team/

3. Polaris Program. Polaris Dawn, a Groundbreaking Commercial Spaceflight Mission, to Launch on August 26, 2024. Prnewswire.com. Published August 19, 2024. Accessed September 11, 2024. https://www.prnewswire.com/news-releases/polaris-dawn-a-groundbreaking-commercial-spaceflight-mission-to-launch-on-august-26-2024-302225455.html