Physicians work to help prevent vision loss associated with space travel

Physicians on the Medical Faculty of Georgia at Augusta College are working with Polaris Dawn, the primary of the Polaris Program’s three human spaceflight missions, to raised perceive the attention adjustments many astronauts expertise throughout spaceflight that may go away them with a variety of signs as soon as they return to Earth—from a brand new want for glasses to important lack of imaginative and prescient.

The Polaris Program is a first-of-its-kind effort to quickly advance human spaceflight capabilities whereas persevering with to boost funds and consciousness for essential causes on Earth.

Greater than 70% of astronauts expertise a phenomenon generally known as Spaceflight Related Neuro-Ocular Syndrome, or SANS, in response to NASA. The syndrome can have “a constellation of signs, together with these adjustments in imaginative and prescient,” mentioned Matt Lyon, MD, director of the MCG Heart for Telehealth.

Astronauts can expertise different maladies as nicely when body fluids, reminiscent of cerebrospinal fluid, shift, which may result in structural adjustments within the mind.

“The adjustments begin occurring on day one,” mentioned Lyon, who can also be the J. Harold Harrison M.D. Distinguished Chair in Telehealth.

“We aren’t solely positive what causes these points with imaginative and prescient, however we suspect it has to do with a shift in cerebrospinal fluid within the optic nerve sheath. On Earth, gravity pushes that fluid down and it drains out, however in space, it floats up and presses in opposition to the optic nerve and retina.”

With the assistance of transportable, handheld ultrasound machines, Lyon and his group hope to not solely determine the mechanism behind the adjustments, but in addition be capable of predict which astronauts will probably be most certainly to expertise them.

MCG patented the idea of utilizing transportable ultrasound to quickly visualize harm from strain and fluid adjustments within the optic nerve sheath, the layers of protecting membranes across the nerve. Lyon is investigating how this a part of the mind is affected by elevated cranial strain and gentle traumatic mind accidents. When the mind is injured, like many different organs, it swells and fills with fluid.

Researchers labored with URSUS Medical Designs LLC, a Pennsylvania-based biotech firm with experience in ultrasound, to construct a 3D ultrasound machine that would assist. A one-year grant enabled the mission to construct a tool that added one other dimension to 2D transducers.

Lyon and the MCG analysis group are actually utilizing these ultrasound machines to display screen astronauts and decide who amongst them could have already got these incompetent or broken optic nerve sheaths. They think that these are those who will probably be extra prone to the imaginative and prescient adjustments related to SANS.

“We found that when the cerebral spinal strain goes up with gentle traumatic mind accidents (TBIs), there may be ensuing harm to the sheath that’s doubtless lifelong,” he defined.

“We predict that when astronauts who’ve skilled concussions or gentle TBIs go into space and expertise the low-gravity fluid shifts, the sheath dilates from the rise in quantity. It is sort of a tire—a standard tire stays its regular form as it’s crammed with air, and the form would not change.

“When it is broken, like bulges on the facet of a tire, the fluid fills the bulges up and the sheath expands. This may trigger strain on the nerve and retina. A broken sheath is much less of an issue on Earth, however in space, the surplus fluid has nowhere to go.”

The researchers do not but know if the imaginative and prescient adjustments are attributable to the sheer quantity of fluid, by the related strain, or each. They’re coaching Polaris Daybreak crewmembers to make use of these ultrasound machines to measure each fluid and strain in actual time throughout spaceflight.

“If it is simply quantity, we suspect the cerebrospinal fluid goes up, fills this floppy bag and will get caught. It is virtually like not flushing your bathrooms. You are creating this poisonous atmosphere, as a result of the cerebral spinal fluid (CSF) is what carries toxins away out of your eyes and nerves, and as an alternative the toxins sit in opposition to the optic nerve, killing it,” Lyon mentioned.

“However it may very well be that mixed with the elevated strain that comes with elevated CSF, which might be like getting intermittent hypertension in your eye.”

Subsequent steps may embody working to develop and positive tune countermeasures that may lower fluid volumes within the head throughout spaceflight. For instance, the U.S. space program and their worldwide space companions use a vacuum-pant system, known as lower-body negative pressure, that pulls blood and different fluids down within the physique.

This experiment will probably be a part of an intensive suite of science and analysis carried out all through the mission. Polaris Daybreak will collaborate with 23 establishments, together with MCG, on the chosen experiments.

Different taking part establishments embody the Translational Analysis Institute for House Well being (TRISH); College of Texas, Houston; College of Colorado, Boulder; Baylor Faculty of Drugs; Pacific Northwest Nationwide Laboratory; and the U.S. Air Drive Academy.