True or false: A single well-defined lower dose threshold has been established for radiation cataracts.

A single well-defined lower dose threshold for radiation cataracts has not been established. Research indicates that there is a range of doses associated with the risk of developing cataracts due to radiation exposure, but the relationship is not straightforward enough to pin down a specific threshold. Studies suggest that cataracts may develop after exposure to relatively low doses, but individual susceptibility, specific radiation types, and other factors contribute to the risk.

The absence of a clearly defined lower dose threshold reflects the complexity of biological responses to radiation. Since cataracts are influenced by various factors, including age and genetics, this enhances the understanding that individual risk cannot be generalized with a single threshold. Therefore, the statement is considered false.