Optic Disc Edema in Astronauts from a Choroidal Point of View

Area of Science:

• Ophthalmology
• Space Medicine
• Neuroscience

Background:

• Optic disc edema is observed in astronauts during and after spaceflight.
• Current theories involve increased intracranial pressure or cerebrospinal fluid sequestration.
• Spaceflight-associated peripapillary choroidal thickening is a potential contributing factor.

Purpose of the Study:

• To propose a novel perspective on the pathogenesis of microgravity-induced optic disc edema.
• To investigate the role of choroidal vasculature and ocular glymphatic outflow.

Main Methods:

• Review of existing literature and studies on spaceflight-associated neuro-ocular syndrome.
• Theoretical modeling of fluid dynamics within the optic nerve head and surrounding structures.

Main Results:

• Prolonged microgravity may cause fluid transudation from choroidal vasculature.
• This fluid may accumulate at the optic nerve head.
• Impaired ocular glymphatic outflow may lead to fluid stasis in the prelaminar region.

Conclusions:

• A choroidal fluid transudation mechanism is proposed for microgravity-induced optic disc edema.
• This viewpoint offers a new understanding of optic disc edema development in astronauts.
• Further research is needed to confirm the role of choroidal fluid dynamics and glymphatic function.