A Computational Model for Retinal Hemodynamics Under Gravitational and Postural Variations

Understanding the effects of gravitational and postural variations on retinal circulation is crucial for both aerospace medicine and terrestrial health. This study presents a computational framework to analyze retinal hemodynamics under different gravitational conditions. A lumped-parameter model was developed to simulate blood flow, intraocular pressure, and vascular adaptations in response to changes in body posture and microgravity. Validation against experimental data demonstrated strong agreement in intraocular and ocular perfusion pressure variations across different tilt angles. Incorporating a simulated 4% constriction of the central retinal artery under microgravity conditions further model accuracy, highlighting the critical role of vascular remodeling. The simulation results indicate that posture significantly affects retinal circulation, leading to notable changes in vessel pressures, arterial velocities, and ocular perfusion. These findings emphasize the importance of fluid redistribution and vascular autoregulatory responses in conditions like Spaceflight-Associated Neuro-ocular Syndrome. This framework offers a powerful tool for developing countermeasures against vision-related risks in spaceflight and has potential applications in terrestrial ocular pathologies associated with altered intracranial pressures.