Astronauts back from space reveal shocking eye problems, Nasa on alert

India Today

6 days ago

Space travel is not easy, especially if astronauts are spending over six months in zero gravity. Nasa is working on alarming vision issues being reported by astronauts on long-duration Space Station missions.When astronauts began spending six months or longer aboard the International Space Station, subtle but concerning changes in their eyesight became impossible to ignore.Many crew members discovered they suddenly needed stronger reading glasses, and medical teams noted swelling of the optic disc (where the optic nerve enters the retina) and a subtle flattening of the eyeball.advertisement
This constellation of symptoms, now known as Space-Associated Neuro-Ocular Syndrome (SANS), represents one of the most significant health challenges for extended space exploration.Microgravity and the Shift of Bodily FluidsAt the heart of the phenomenon is zero gravity. Without the pull of Earth's gravity, blood and cerebrospinal fluid tend to accumulate in the upper body and head. Mounting evidence suggests these 'headward' fluid shifts play a key role in SANS, potentially increasing pressure in the brain and affecting the eyes.One active investigation, known as the Thigh Cuff experiment, is exploring whether tight cuffs around the legs can prevent or reverse this process by trapping blood in the lower body. If successful, this solution could protect astronauts on future lunar and Mars missions, and may also help patients on Earth who suffer from similar fluid distribution issues due to disease or long-term bed rest.'Pioneering Studies and New DiagnosticsBetween 2015 and 2020, the landmark Fluid Shifts study offered the first direct evidence of altered blood drainage from the brain in weightlessness.The Vision Impairment and Intracranial Pressure (VIIP) project further probed the relationship between fluid shifts, increased brain pressure, and the development of SANS. Researchers employed a battery of advanced techniques, including:Comprehensive eye exams (with and without pupil dilation)High-resolution retinal imagingNoninvasive measures of retinal thicknessMRI scans of the eyes and optic nervesResults from hundreds of astronauts were also collected through detailed questionnaires, providing essential context for the objective findings.Exploring Treatments Novel technologies are changing the way SANS is detected and possibly managed. Researchers are developing a head-mounted virtual reality display for multimodal, noninvasive assessment, and optic nerve sheath diameter measurements have emerged as a promising diagnostic tool.Calls are also growing for standardised imaging and study protocols, which could streamline future research and treatment efforts. In a particularly notable case, one astronaut who developed unusually severe SANS symptoms after six months in space experienced marked improvement.This recovery coincided with B vitamin supplementation and a reduction in cabin carbon dioxide following crew rotations, suggesting potential roles for targeted nutrition and habitat environment in risk mitigation.Eye Structure, Genetics, and Artificial GravityadvertisementCanadian studies using Optical Coherence Tomography have shown that long space missions can change the mechanical properties of eye tissues, similar to what's seen in age-related eye conditions like glaucoma.Meanwhile, research by the Japan Aerospace Exploration Agency found DNA and gene expression changes in the optic nerve and retina of mice after spaceflight, with early evidence that artificial gravity could help counteract these effects.Ongoing investigations are critical, not only for safeguarding crew on the ISS but also for future missions to the Moon, Mars, and beyond, and may unlock new treatments for terrestrial diseases marked by fluid shifts and eye changes.- EndsTrending Reel