SANS

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A significant number of astronauts—approximately 70%—return from long-duration space missions with persistent vision problems, a condition known as Spaceflight Associated Neuro-ocular Syndrome (SANS). This issue has become a major concern as NASA plans for extended missions to the Moon and Mars.(ScienceAlert)

What Is SANS?

SANS encompasses a range of visual and structural eye changes, including:(humanresearchroadmap.nasa.gov)

• Optic disc edema (swelling of the optic nerve head)

• Globe flattening (a change in the shape of the eyeball)

• Hyperopic shifts (increased farsightedness)

• Choroidal folds (wrinkles in the vascular layer of the eye)(Wikipedia)

These alterations can lead to blurred vision, difficulty reading, and other visual disturbances. Unlike temporary issues such as motion sickness, these vision changes can be permanent and may not fully resolve after returning to Earth.(ScienceAlert)

Causes of SANS

The primary suspect is microgravity, which causes bodily fluids to shift toward the head. This redistribution increases intracranial pressure, which in turn affects the eyes and optic nerves. On Earth, gravity helps maintain fluid balance, but in space, this mechanism is disrupted, leading to the observed eye changes.(Eyes On Eyecare, Wikipedia, medicine.iu.edu)

Implications for Future Missions

The potential for permanent vision impairment poses significant risks for long-duration missions, such as those to Mars, which could last 2–3 years. Astronauts with compromised vision could face challenges in performing critical tasks, including piloting spacecraft and conducting scientific experiments.(ScienceAlert)

NASA's Response and Research

NASA is actively investigating SANS and developing countermeasures to mitigate its effects:(Space)

• Visual Impairment Intracranial Pressure (VIIP) Chamber: A device designed to simulate Earth-like pressure conditions to maintain normal eye function during spaceflight.

• Pharmacological Interventions: Exploring medications that could reduce intracranial pressure and prevent eye changes.

• Exercise Protocols: Developing in-flight exercise routines to promote fluid distribution and reduce pressure on the eyes.

• Advanced Imaging Techniques: Utilizing tools like Optical Coherence Tomography to monitor eye health and detect early signs of SANS.(Space, Wikipedia, The Times of India, humanresearchroadmap.nasa.gov)

These efforts aim to ensure that astronauts can undertake long-term missions without jeopardizing their vision and overall health.(Wikipedia)

Broader Implications

The research into SANS not only addresses the needs of astronauts but also has potential applications for treating eye conditions on Earth. Understanding how pressure affects vision could lead to new treatments for diseases like glaucoma and intracranial hypertension.

For more detailed information, you can read the full article on ScienceAlert: .