Approaching ocular risks during spaceflight with 3D printing: Technical strategies to protect astronaut vision.

Long-duration spaceflight poses significant risks to ocular health due to prolonged microgravity exposure and space environmental stressors, contributing to conditions such as Spaceflight-Associated Neuro-ocular Syndrome (SANS) and Spaceflight-Associated Dry Eye Syndrome (SADES). These conditions, along with radiation exposure and risk of ocular trauma in resource-limited environments, necessitate development of innovative countermeasures to safeguard astronauts' vision, particularly for future planetary missions such as Mars. Traditional ophthalmic care depends on specialized equipment and materials impractical for cargo limitations and transport in space, highlighting the need for adaptive solutions. Advances in 3D printing and bioprinting offer an innovative approach to space ophthalmology by enabling on-demand fabrication of customized eyewear, contact lenses, moisture chambers, radiation-shielding lenses, and surgical tools. Furthermore, emerging bioprinting capabilities may facilitate production of biocompatible tissues for ocular repair. The precision, adaptability, and mission-specific applicability of 3D printing provide a strategic advantage to address preventive and therapeutic ocular health needs. However, challenges include optimizing biocompatible materials, refining high-resolution printing techniques, and ensuring structural and functional viability of printed tissues in space conditions. Further research is required to improve material durability, integrate protective elements such as boron nitride nanotubes, and adapt 3D printing processes to the constraints of microgravity. Beyond space medicine, 3D printing applications in space can drive innovations for ophthalmic care on Earth, from customized intraocular lenses to regenerative therapies. This review highlights the critical role of 3D printing in space ophthalmology and need for continued development and deployment to ensure success of future deep-space missions.