Abstract
Purpose :
This study assesses the impact of extended microgravity exposure on ocular rigidity, intraocular pressure, and ocular pulse amplitude following long-term space missions.
Methods :
Ocular rigidity (OR), a measurement of scleral stiffness, was evaluated using a non-invasive method, utilizing optical coherence tomography (OCT) videos and complemented by deep learning-based choroid segmentation. Intraocular pressure (IOP) and ocular pulse amplitude (OPA) were measured with the PASCAL Dynamic Contour Tonometer (DCT). Initial measurements were taken within six months of mission commencement and within 30 days post-landing.
Results :
The study included 26 eyes from 13 crew members (average age: 49±10 years; 31% females). Initial ophthalmological examinations revealed no pathological findings. All subjects participated in extended space missions aboard the International Space Station, lasting from 157 to 186 days. Novice crew members constituted 35% of the cohort. Following the mission, there was a significant average decrease in OPA, measured by the Pascal tonometer, of 25% compared to baseline (p < 0.005). Additionally, there was a significant 11% decrease in intraocular pressure from 16.0 mmHg to 14.2 mmHg (p = 0.04). For the analysis of ocular rigidity, involving 17 eyes from 9 astronauts, we found a significant 33% reduction post-mission compared to baseline (p = 0.04). No disparities were observed between senior and novice astronauts.
Conclusions :
The data indicate a substantial decrease in ocular rigidity, intraocular pressure, and ocular pulse amplitude after space missions. These observations reveal previously unknown effects of microgravity on the eyes and may contribute to a deeper understanding of space flight-related neuro-ocular syndrome.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.