Which of the following is an example of a non-stochastic effect?

Cataracts are an example of a non-stochastic effect because they are directly related to the dose of radiation exposure and have a clear threshold. Non-stochastic effects, also known as deterministic effects, are characterized by their severity increasing with the dose and having a specific threshold level; below this level, the effect does not occur.

In the case of cataracts, there is a dose-related response where higher doses of radiation increase the likelihood of developing this condition, and there is a specific dose threshold above which the risk of cataract formation significantly increases. This means that the occurrence and severity of cataracts can be predicted based on the amount of exposure to radiation.

In contrast, stochastic effects, such as bone cancer, leukemia, and genetic mutations, occur randomly and the risk of these conditions increases with the dose of radiation, but there is no threshold. Even small doses carry a risk of causing stochastic effects, making them fundamentally distinct from non-stochastic effects like cataracts.