Persistent Asymmetric Optic Disc Swelling after Long-Duration Space Flight: Implications for Pathogenesis

Background:Several ophthalmic findings including optic disc swelling, globe flattening and choroidal folds have been observed in astronauts following long-duration space flight. The authors now report asymmetric choroidal expansion, disc swelling and optic disc morphologic changes in a 45-year-old astronaut which occurred during long-duration space flight and persisted following his space mission. Methods:Case study of ocular findings in an astronaut documented during and after a long-duration space flight of approximately 6 months. Before, during and after his spaceflight, he underwent complete eye examination, including fundus photography, ultrasound, and optical coherence tomography. Results:We documented asymmetric choroidal expansion inflight that largely resolved by 30 days postflight, asymmetric disc swelling observed inflight that persisted for over 180 days postflight, asymmetric optic disc morphologic changes documented inflight by OCT that persisted for 630 days postflight and asymmetric globe flattening that began inflight and continued 660 days postflight. Lumbar puncture opening pressures obtained at 7 and 365 days post-mission were 22 and 16 cm H20 respectively. Conclusion:The persistent asymmetric findings noted above, coupled with the lumbar puncture opening pressures, suggest that prolonged microgravity exposure may have produced asymmetric pressure changes within the perioptic subarachnoid space.