Space Radiation Effects on the Glutathione Redox Cycle and Cataract Formation.

Abstract

Introduction: With increasingly ambitious space ventures, astronauts face numerous hazards, including radiation, isolation, altered gravity fields, and hostile environments. Cataracts pose a significant challenge to astronauts' health and performance, both in space and upon returning to Earth. These concerns intensify with deep space exploration, where exposure to high-energy ionizing radiation in the form of galactic cosmic rays, solar particle events, and heavy ions accelerate cataract development.

Methods: This review synthesizes research from Embase, Google Scholar, Web of Science, Grey Literature, PubMed, and NASA sources on cataracts, radiation, and spaceflight.

Results: Of 3308 articles identified, 595 duplicates were removed, 476 met inclusion criteria, and 392 were included in the analysis.

Discussion: Radiation-induced cataract pathophysiology consists of ionizing radiation induced oxidative stress, which increases free radicals while depleting glutathione. Glutathione is a key antioxidant that interacts with ascorbic acid to protect the lens. Once glutathione levels are compromised, oxidative damage promotes protein aggregation and opacification of the lens, resulting in cataract formation. Countermeasures include optimizing antioxidant defenses, intraocular lens placement, and implementing operational and biomedical strategies such as radiation shielding and protective eyewear. Understanding and addressing these risks is essential for ensuring astronaut visual health and mission success in prolonged space exploration. Katsev BD, Lee R, Kim JH, Leigh A, Ong J, Waisberg E, Lacy AJ, Mader TH, Gibson CR, Berdahl J, Lee AG. Space radiation effects on the glutathione redox cycle and cataract formation. Aerosp Med Hum Perform. 2026; 97(5):354-361.