Head-Down Tilt As a Model for Intracranial and Intraocular Pressures, and Retinal Changes during Spaceflight (Subcutaneous Tissue and Subdural Space, Body Temperature and Intracranial Pressure Biotelemetry)

Retinal morphology and ultrastructure were examined at specified intervals both during HLS and post-HLS recovery by ophthalmic examinations. This program utilized both male and female subjects in order to examine possible sex differences in these responses. We also examined the possible contributory factors of aging and elevated atmospheric carbon dioxide (hypercapnia) on these responses of the visual system.

Further, in addition to mimicking the effects of long duration exposure to microgravity through the use of the HLS model, we examined the responses of our measured outcomes during long-term recovery in the post-HLS period. Collectively, these data will help us to develop a model to both understand and predict the etiology of changes in visual structure and function in astronauts exposed to the microgravity of spaceflight and during postflight recovery.

This study investigated the development of a translational mammalian model within the context of hindlimb unloading, sex, and aging by which the data generated using this model can facilitate the development of countermeasures to alleviate any visual system decrements arising from exposure to the microgravity spaceflight environment. This study derives results from Biotelemetry (body temperature and intraocular pressure) assay using implants in the subcutaneous tissue and subdural space.

This study is related to results found in OSD-679 (eye) and OSD-680 (optic nerve).