Nasal Neurostimulation as a Countermeasure for Dry Eye Disease in Astronauts: Feasibility Study in Microgravity During Parabolic Flights

Dry eye disease is common in astronauts during long-duration spaceflight and causes symptoms that impact comfort and performance. Conventional treatments such as eye drops are impractical in microgravity, creating a need for alternative countermeasures. This preliminary study assesses the feasibility of using the iTear100 device for neurostimulation in microgravity during parabolic flight. Thirteen healthy participants were exposed to microgravity phases while undergoing external nasal mechanical neurostimulation. Tear secretion was assessed using a high-resolution infrared imaging system (TearView, Beyond700 Ltd., Sydney, Australia), and tolerability was measured using a modified Treatment Tolerability Scale. Neurostimulation was well tolerated, induced perceptible tear production in all participants, and was deemed safe in the microgravity environment. These findings support the use of neurostimulation as a non-pharmacological, reusable treatment for dry eyes during spaceflights.