Radiation-induced cataract in astronauts and cosmonauts

Background: Opacification of the ocular lens is an important effect of exposure to ionizing radiation. Astronauts and cosmonauts are exposed to relatively high doses of all types of radiation in space, including high-energy particle radiation. A study was initiated to examine the lenses of the eyes of astronauts/cosmonauts to detect signs of radiation-induced cataracts. The aim of this study was to take a first step towards gaining improved, quantitative insight into the risk of radiation-induced cataract associated with long space missions. Methods: The lenses of 21 former astronauts and cosmonauts were examined, using an upgraded Topcon SL-45 B Scheimpflug camera system. The degrees of opacification in this group of astronauts and cosmonauts were compared with the measurements in a reference group. This reference group was established by examining a cohort of 395 persons using the same Scheimpflug system. Results: Initial results indicated that opacity values in most of the astronauts and cosmonauts were slightly to strongly increased in regions TV (posterior cortex) and V (posterior capsule), compared with the average opacity values for the respective age-group of the reference cohort. Conclusion: The aim of this study - to conduct first examinations of astronauts' and cosmonauts' ocular lenses with regard to signs of radiation-induced cataract - was successfully achieved in a total of 21 astronauts and cosmonauts using a Scheimpflug camera system. It is planned to examine a larger group of astronauts and cosmonauts in the future.